How long is your migration to Office 365 going to take?

 Your rate limiting step in a migration is moving and synchronizing your email.

It's going to take weeks at a minimum if you have a site of any size.  More likely it will take months.

Why?  Because likely you have over 100 Gb of email files and that's just going to take a while to process and (thanks to the IMAP protocol) continuously synchronize until your cut-over date.

The IMAP protocol is a godsend for these purposes.  So getting started early and watching the amount of data you have and have moved is going to be a key part of the process. 

Sadly, no ready protocol exists for calendars, contacts, and tasks.  So you need to one-off those and you should expect them to take hours just before cut-over.

That's why testing the snot out of everything is our mantra.

Latest version of imapsync includes web interface!

Woo hoo!

The latest version of imapsync includes a web interface:

Try it out at  https://imapsync.lamiral.info/X/

Calendar Migrations: The 80/18/2 rule

Enterprise migrations are as much a social engineering issue as a data conversion issue.

Keep in mind, we're talking organizations here as opposed to single-users, and we're focused on server-to-server solutions as opposed to client-to client solutions.

Let's get into that social engineering by way of the perceived utility among your user base, shall we?

If you're acquainted with the 80/20 rule, we're going to give you, based on our experience of doing this kind of stuff since 2001, our own 80/18/2 rule when it comes to migrating into Exchange or Office 365.

To wit:

• 80% of what you need to migrate is email.
• 18% is calendars (full-state or flat, doesn't matter), contacts, tasks 
• 2% is user preferences, settings, delegates 

Getting 80% done should cost you NOTHING

Email is manageable with imapsync and your cost is  €100 EUR for product and support no matter your enterprise size.  Why on earth would you pay anybody for email migration when this is available (unless you have a backroom deal with a consultant)?  We've even done a couple of guides one of which you can download here.

We've done several posts on how to use imapsync to migrate into Exchange / Office 365.

If all you (need to) care about is email you're done here.

Your likely result in this 80%:  
Your end-user efforts: Minimal
Your Admin efforts: Moderate to high
Your End User Satisfaction: Moderate (if you stop here)

Your next 18%

Contacts and tasks are not other-user-connected information and (worst case) you can move them via CSV/TXT file methods.

Calendars are a more complex discussion.  In fact this entire blog is dedicated to migrating calendars and keeping as much of the useful connections between users intact.

Anybody who's promising you "no data loss" in a migration and takes calendars without re-creating the guest list has been dealing in alternate facts.

If you do not care about attendees, attendee responses, and resource bookings, there are a variety of solutions.  If your enterprise wants "no data loss" when it moves to a new collaboration platform, i.e.,  to keep its meetings as meetings, please search this blog for the legacy system and read the appropriate articles.

We do charge for that capability.

Your likely result in this 18% with Sumatra methods: 
Your end-user efforts: Minimal
Your Admin efforts: Moderate to high (depends on experience level)
Your end-user satisfaction: HIGH

Your likely result in this 18% without Sumatra methods:  
Your end-user efforts: HIGH (Need to re-create meetings, resource bookings)
Your Admin efforts: Low.  (We have seen sites choose based on Admin efforts -- their call)
Your end-user satisfaction: Low to moderate

The final 2% (the last mile to the finish line)

Let's talk about that last part since it's portrayed out of proportion to its time value: 

• User preferences, 
• Delegates
• Junk Mail filtering rules
• Client-side Outlook re-configuration

User Preferences
Many of these are scriptable.
One of us has in fact has been itching to write about how to script user preference migration so keep an eye on this blog.
The important things to keep in mind here are:

1. From almost any legacy system there is going to be a disconnect between user preferences offered and Exchange / Office 365.
2. Even if there is not a disconnect in a specific functionality, the question is can you get at the legacy data via server-side utilities?
3. Setting user preferences is a great opportunity (a "teachable moment") to enforce encourage your users getting training and actually taking steps in Exchange before or after a migration.

Delegates
You would LIKE to think Delegates are a simple matter.

This is exactly incorrect.

First off, because the model for delegates is usually very different between your legacy system and Microsoft Exchange.  Example: In Oracle Calendars delegate access (called Designate access in OCS) is OBJECT-BASED and in Exchange it's FOLDER-BASED.  

Second because over time the number of delegates in legacy systems has usually out-grown the organization's needs and some re-thinking is most definitely in order.  During a migration is the perfect time to reset those access permissions. Or, worst case, you migrate all legacy delegates (and we mean it’s the worst case.) 

Third because after you set those delegate permissions in Exchange you discover that users can edit conference room bookings, and can see other’s calendar information. What’s the worst case: there is no good way to reverse the permissions.  Exchange has some native peculiarities that you're not going to really understand until you're in the thick of actually production deploying it and then it's either too late to change or a pain in the neck to re-do.  See: Two ways to grant access to a Resource in #MSFTExchange.

While it is possible to devise very clever technical solutions (and we have!) experience in this shows that (in stark contrast to a full-state calendar migration) it always leaves a subset of users grumbling that it did not do what they wanted.  

And grumbling is the enemy of a successful enterprise migration.  We prefer a few whining grumbling users to the entire organization ready to “run you out of town.”

Our conclusions from doing these: The effort is better spent as a training opportunity to get users active in setting up their delegates post-migration. 

Junk Mail / filtering Rules

This is potentially a real pain.  Thunderbird HAD a tool for email filtering migration but it's atrophied.

While Microsoft makes it possible to export rules from Outlook and import them to other Outlook clients, in general the methods for taking rules from legacy systems and migrating them simply to Outlook are lacking. And we've never seen it done server-side.


Best strategy we've seen for those who need to deal with it is to identify the high need individuals and get them or their admins training to help re-create essential rule sets. 

Client-side Outlook re-configuration
If users were using Outlook as a client in your legacy system you need to point them all to your Exchange domain now.

Not too difficult.  See Deploy Outlook mail profile settings via GPO or script

The process as described in that link is solid, but we have found problems with the VB script in it. If you are a Sumatra client please feel free to ask us for our VB script:  deployprf.vbs

Your likely result in this 2%:  Experience tells us user response is almost a complete crap-shoot if you try to automate it.  Best you can hope for is a low complaint level.  No one is ever really grateful for it.
Your end-user efforts: Low to Moderate
Your Admin efforts: Moderate to high
Your end-user satisfaction: it’s dependent upon end-user communication and expectation management

Tips and tricks for optimizing IMAP migrations from Microsoft

Good to see this:

Tips and tricks for optimizing IMAP migrations: https://t.co/UH5MCjrVVR pic.twitter.com/MEPMya69rh

— Microsoft Exchange (@MSFTExchange) August 24, 2016

 But they left out the most important suggestion:  evaluate imapsync instead of Microsoft's black box.

Email Migration Microsoft Exchange to Office 365 via imapsync

Yet another in the ever-expanding popular series of how to use imapsync (one of the best low-cost tools available) to migrate email to Exchange.  This time for Microsoft Exchange to Microsoft Exchange or Office 365.

Yes.  Microsoft offers tools for this, and we've documented them.

Evaluate them yourselves.  We have.  That's why we recommend imapsync. Full disclosure: we have no relationship with imapsync and derive exactly zero revenue from this non-existent relationship.

We see a wide spectrum of Exchange expertise (*cough* admin at university in Pennsylvania stymied by Junk E-mail folder *cough*) so we think it's useful to document this process.

Your comments are welcome and will be added and credited.

First step:
Make sure you are enabled for IMAP on both sides of your Exchange migration. 
We've gone over this in our post Quick guide to Enabling IMAP in @Office365 / #MSFTExchange 2013.

Second step:
Set up a Service Account with access to all your Exchange accounts. Confused about Exchange permissions and setting up your service account?  Read our post The Cookbook Version of Exchange 2013 Migration Rights.

Third step:
Test this before you do something rash.

Gilles (imapsync's AWESOMELY capable  author who deserves HUGE credit for his application) has a sensible method of beginning in his sample batch file (seen in this excerpt):


...

@REM Three other options are in this example because they are good to start with
@REM
@REM --dry makes imapsync doing nothing, just print what would be done without --dry.
@REM 
@REM --justfolders does only things about folders (ignore messages). It is good
@REM               to verify the folder mapping is good for you.
@REM
@REM --automap guesses folders mapping, for folders like 
@REM           "Sent", "Junk", "Drafts", "All", "Archive", "Flagged".

@REM

...

Or: do a DRY run, make sure it's handling the folders you want, and let the application guess on your folder mapping (for Microsoft Exchange to Office 365 or Exchange not complex).

Not too controversial or inscrutable, right?

So for ONE USER where you have the password for that user on BOTH systems start with:


imapsync.exe ^

--host1 sumatra.com --user1 jimi.hendrix@sumatra.com --password1  "XXXX" ^
--host2 outlook.office365.com --user2 ^
jimi.hendrix@sumatra.onmicrosoft.com --password2 "XXXXX"  ^
--ssl2  --sep2 /  --dry --justfolders --automap

once things are doing what you want, you can turn this into:

imapsync.exe ^
--host1 sumatra.com --user1 jimi.hendrix@sumatra.com --password1  "XXXX" ^
--host2 outlook.office365.com --user2 ^
jimi.hendrix@sumatra.onmicrosoft.com --password2 "XXXXX"  ^
--ssl2  --sep2 /  --automap

If you set up a service account with FullAccess on Office 365, you accomplish a migration without knowing any password except your service account by using a command like this (where password2 is the service account password):

imapsync.exe ^
--host1 zimbra.sumatra.com  ^
--user1 jimi.hendrix@zimbra.sumatra.com --password1 "XXXX" ^
--host2 outlook.office365.com --port2 993 --sep2 / ^
--user2 jimi.hendrix@sumatra.onmicrosoft.com ^ 
--authuser2 SERVICE_ACCT@sumatra.onmicrosoft.com ^
--password2 "XXXXX"  --ssl2  --dry --justfolders --automap

remember --dry --justfolders are for debugging.

Note in  the above, for an Office 365 target system we need to use the "--sep2 /" command. 
Note also that this gives you the direct capability to map your user ID, for instance from "jimi.hendrix" on your legacy system to "jhendrix1967"  or "jimi.hendrix1967" on your target system.

Iterating over a user list
In any event you are going to need to generate a user list to migrate email.  Can you keep your migrating user list separate from your migration script?  Answer: YES. This method assumes your legacy ID is the same as your target ID, but allowing for this to change is not a hard extension.

The imapsync ZIP file contains a script for iterating on a user list:
sync_loop_windows.bat
Which also contains an excellent primer on running imapsync in parallel.
This batch file assumes a text file in the form "User1;Password1;User2;Password2;..."  (TIP: If you use a service account you will not need the password)

To get  a user list from Exchange get-mailbox is the simplest method :

get-mailbox | fl name,emailaddress   > myusers.txt

to give you full name, email address.

For just email address run:

get-mailbox | emailaddress   > myusers.txt

You could also use ldapsearch if you already have scripts for that.

If you want to get a list of all users in an OU to migrate by segments: 
get-mailbox (e.g., -organizationalunit users

More Migration Details

Throttling in Exchange/Office 365
You're more likely to be throttled in Office 365 since the controls to that environment are largely out of your hands.

As per our usual mantra: test everything before you go into production.

If you get throttled, there are two imapsync switches you can tweak.

One limits the transfer rate to a specific number of messages:
--maxmessagespersecond

Start at 10 (say) and work up or down from there.  In calendar migrations we start with 25, but our gut experience tells us calendar data is smaller per object on average.

The other limits the transfer rate by byte if that works better for your network environment.
--maxbytespersecond

You can also check out our post Throttling in Exchange 2013.

Really helpful options
--buffersize 8192000  imapsync has a default I/O buffer of 4 Kb.  Upping this to 8 Mb will probably speed things for you
--syncinternaldates: Not for Exchange, but some email systems misuse email dates and you therefore run the risk of the receipt dates on your target system (what imapsync refers to as host2) becoming the date of insertion.  This command avoids that unfortunate event.
--fast:  this prevents flags from being synced and therefore makes the process (wait for it....) faster.  Not an option to invoke if you want / need to sync flags!
--dry:  this is a really useful option for development and debugging,  It just goes through the motions of logging onto both source and target system and displays the status -- a dry run.  Use this or debugging options -debug and -debugimap

See our section on Common Problems and Solutions in our Sumatra's DIY Guide to an Office 365 Migration.

Update to #Zimbra to #Office365 Email Migration using @imapsync

As an update to our post #Zimbra Email Migration to #Office365 using #imapsync  

On the issue of mapping folder names, use imapsync 1.678 and its 

--automap option.  This is now pre-populated with best guesses for Exchange as a target (if I read the release notes correctly)

If --automap does not work directly for Zimbra to Exchange, then use

--f1f2 str1=str2 

for example:

--f1f2 Junk=Junk E-Mail to map Zimbra's "Junk" folder to Exchange's "Junk E-Mail."

Microsoft Exchange to Office 365 Calendar Migration Preserving Meetings as Meetings

Microsoft does not offer full-state calendar migrations from Exchange to Office 365.

Your meetings will all become appointments.  It's like printing your calendars from one Exchange system into office 365.

If you're a small site this is no big deal and easily managed.

If you're an enterprise where people live in meetings and conference room and resource allocation is crucial this can be a huge hassle which can delay your migration to the cloud.

If you use our technology your meetings will stay meetings. Problem solved.

And this shows synchronization working, again with full-state meeting migration, from one Exchange environment to another:

Since we added sync for meetings we also did it for tasks and contacts. 

And of course this is fully-mappable and includes our UNDO capability for easy testing and disaster recovery.

Why don't we do email as well?  Because imapsync does a superlative job for 100 Euros for any number of seats!  We cannot beat that.  Actually I do not think anyone can beat that.

Given the popularity of our MDaemon to Exchange and Zimbra to Office 365 email migration guides we're seriously considering an Exchange to Exchange email migration guide for imapsync.  Stay tuned.

If you do not need or want all that utility we have an option that runs faster but still tells you who is supposed to be in your meetings.  This is the information no one else provides you.

If you need Microsoft Exchange to Microsoft Office 365 calendar migration, feel free to contact us.

#Zimbra Email Migration to #Office365 using #imapsync

Today we'll show you how to use imapsync to migrate email from Zimbra to Exchange 2013 / Office 365.  We got some good feedback from our initial post on Zimbra calendar migration to Microsoft Exchange and wanted to add some value on the issue of email migration.  When we did that for MDaemon everyone was very grateful and it led to much calendar migration.

You can license the technology and purchase the support to migrate your email for 100 Euros. Remember this only moves email.  You will have to budget additional funds to move your calendars.  This gives your end users a complete solution -- email and "live" (with guest lists and responses.) Plus, your conference rooms and resources are fully functional when you're done with your migration.  That's what we do at Sumatra.

We found imapsync to be the most  efficient and cost-effective, email migration product.  Just license imapsync and get support at the same time.

Is this imapsync email migration guide exhaustive?  Hell no!  There is no way to document all the "creative" ways user behavior can wreak havoc -- and some of them are going to be downright pathological.  We are aiming for the 80% side or the 80/20 rule here.  You get that much down you can make a good stab at the rest if you find yourself in difficulties. Barring that imapsync is very forgiving and its model of incremental syncing is laudable in its simplicity and effectiveness.

Migrating your email probably also takes you through 80% of what you need in a migration.  If you're happy with that -- glad to be of service.  If you need the calendaring to come over with fully-functional meetings, guest lists, responses, resources, contact Sumatra and we'll set you up with a trial.

Preliminaries

Zimbra has excellent guide on using imapsync with Zimbra.  We would suggest you add a valid non-self-signed certificate to their requirements.  imapsync runs in Linux and Windows (via the Command Prompt.) We'll demonstrate the Command Prompt since Microsoft Exchange / Office 365 is our target system.  Editorial comment: one of the smartest things Microsoft could do is put Exchange on Linux, but it's more likely some weenie there will recommend porting Windows to the iPad first.

Remember before you test,  you will have to enable IMAP in Exchange 2013 and for your end users in Office 365.  See how to do this in our blog post.

Migrating one user Zimbra to Exchange

In the simplest case migrating from Zimbra to Office 365 looks like this for our user Jimi Hendrix (if you use individual passwords for users).

imapsync.exe ^

--host1 sumatra.com --user1 jimi.hendrix@sumatra.com --password1  "XXXX" ^
--host2 outlook.office365.com --user2 ^
jimi.hendrix@sumatra.onmicrosoft.com --password2 "XXXXX"  ^
--ssl2  --sep2 /

If you set up a service account with FullAccess on Office 365, you accomplish a migration without knowing any password except your service account by using a command like this (where password2 is the service account password):

imapsync.exe ^
--host1 zimbra.sumatra.com  ^
--user1 jimi.hendrix@zimbra.sumatra.com --password1 "XXXX" ^
--host2 outlook.office365.com --port2 993 --sep2 / ^
--user2 jimi.hendrix@sumatra.onmicrosoft.com ^ 
--authuser2 SERVICE_ACCT@sumatra.onmicrosoft.com ^
--password2 "XXXXX"  --ssl2

Note in  the above, for an Office 365 target system we need to use the "--sep2 /" command. 

Confused about Exchange permissions and setting up your service account?  Read our post The Cookbook Version of Exchange 2013 Migration Rights.

If you want to use a Service Account on Zimbra as well, similar syntax should work using either the "admin" or "zimbra" account.

Note also that this gives you the direct capability to map your user ID, for instance from "jimi.hendrix" on your legacy system to "jhendrix1967"  or "jimi.hendrix1967" on your target system.

Iterating over a user list

In any event you are going to need to generate a user list to migrate email.  Can you keep your migrating user list separate from your migration script?  Answer: YES. This method assumes your legacy ID is the same as your target ID, but allowing for this to change is not a hard extension.

The imapsync ZIP file contains a script for iterating on a user list:

sync_loop_windows.bat

Which also contains an excellent primer on running imapsync in parallel.  

This batch file assumes a text file in the form "User1;Password1;User2;Password2;..."

Zimbra's Guide to imapsync includes a couple of batch processing script examples.

To get  a user list from Zimbra you can use either zmprov (this gets a list of accounts without passwords, so use a Zimbra admin account to get data, and please edit out the spam, A-V, etc. IDs): 

cd /opt/zimbra/bin  

and 
sudo ./zmprov -l gaa >~/accounts.txt

You could also use ldapsearch if you already have scripts for that. 

It has been said that the "death is in the details."  We say, "success is set in the details."

Now come the details

Throttling in Exchange/Office 365: Your Migration Nemesis

Note that I did not write "enemy."   You're more likely to be throttled in Office 365 since the controls to that environment are largely out of your hands.

As per our usual mantra: test everything before you go into production.  

If you get throttled, there are two imapsync switches you can tweak.

One limits the transfer rate to a specific number of messages:  
--maxmessagespersecond

Start at 10 (say) and work up or down from there.  In calendar migrations we start with 25, but our gut experience tells us calendar data is smaller per object on average.

The other limits the transfer rate by byte if that works better for your network environment.

--maxbytespersecond

You can also check out our post Throttling in Exchange 2013.

Really helpful options

• --buffersize 8192000  imapsync has a default I/O buffer of 4 Kb.  Upping this to 8 Mb will probably speed things for you
• --syncinternaldates: some email systems misuse email dates and you therefore run the risk of the receipt dates on your target system (what imapsync refers to as host2) becoming the date of insertion.  This command avoids that unfortunate event. 
• --fast:  this prevents flags from being synced and therefore makes the process (wait for it....) faster.  Not an option to invoke if you want / need to sync flags! 
• --dry:  this is a really useful option for development and debugging,  It just goes through the motions of logging onto both source and target system and displays the status -- a dry run.  Use this or debugging options -debug and -debugimap

Other idiosyncrasies

The imapsync FAQ recommends these additional settings when migrating from Zimbra.

imapsync ... ^
--exclude "Conversation Action Settings" ^
--exclude "Quick Step Settings" ^
--exclude "News Feed"

Although we have not seen those folders in Zimbra in a while, your implementation could be different.

Sent, Junk, and Trash

However, there are differences in Folder names between the two environments that may be relevant to you.  Specifically what Zimbra calls "Sent, Junk, Trash" Office 365 calls "Sent Items, Junk E-Mail, Deleted Items" as seen in this side-by-side comparison.

To successfully migrate these folders, use this command sequence to map the folders: (see Zimbra Documentation):

--regextrans2 's/Sent$/Sent Items/'
--regextrans2 's/Junk$/Junk E-Mail/'

--regextrans2 's/Trash$/Deleted Items/'

Notice how we lined these up so it would be easy to repeat if you needed this for other systems, or different language packs.  These being regular expressions you could also take several related folders and migrate them into a single one on the Office 365 side, but I leave that to your wits and imagination.  If you do find something that works, let us know -- we'll update this post (of course, crediting you!)

Exchange IMAP Prerequisites

Did you configure IMAP?  If not, see how in our blog post:

On the Zimbra side:
Make sure you are enabled for IMAP access. 

Check "Enable clear text login" for the IMAP service via "Global Settings" or under "Servers" under IMAP in the Zimbra Administration Console.

If you need to install Perl modules, this is an excellent tutorial on how to do so.

Sample Scripts

These sample scripts for major migrations / multiple users will help you out a lot.

http://imapsync.lamiral.info/examples/sync_loop_windows.bat

http://imapsync.lamiral.info/examples/file.txt

Final word on really considering what you need in Zimbra migrations Diatribe: Migrating email is about moving tonnage.  Migrating calendars is about preserving responses, recurrences, and resources.

But a full migration methodology has to include more than just moving this data. We have a comprehensive suite of scripts and tools so that before any email or calendars are migrated we take care of:

• Reading the Zimbra user list (and passwords)
• Provisioning users in Exchange
• Re-configuring Outlook to point to your Exchange server and removing the Zimbra Outlook connector. (Note: there are publicly available scripts but we wrote our own after we found they did not work.)
• Pre- and Post-cut over scripting so that legacy emails are moved to the target system, and new emails redirected to the target system.

If you have a few dozen users, it's difficult to make an automated process cost-effective and you might as well do it on your own one at a time.  You can export PSTs or export files from Zimbra, then import those PSTs into Exchange.  Tedious and time-consuming, yes, but free.

If you are a larger site with the need to preserve your meeting guest lists, recurrences, responses, and resources post-migration feel free to contact Sumatra.

Quick guide to Enabling IMAP in @Office365 / #MSFTExchange 2013

Let's say you're going to want to start migrating email from a legacy system like Zimbra into Exchange 2013 or Office 365.  You're going to need to get IMAP running on either your on-prem Exchange environment or in O365.

This tells you how to do it.

In a few days we'll show you how to start moving your Zimbra email.  Why are we picking on Zimbra?  We're not, we're responding to market demand to move Zimbra (which is not hard to see since Exchange continues to improve linearly and Zimbra has developed in fits and starts from being independent to being a quizzical part of Yahoo to being remaindered to VMware to passed off to Telligent and now just sold to Synacor). 

There are three pieces to get IMAP working:

1. Start the IMAP service (Exchange 2013.)  Office 365 can skip this step
2. Enable the IMAP Connector
3. Enable the IMAP mailbox feature for user accounts

Start the IMAP Service

The first step is to start IMAP on your Exchange 2013 server (see below).  Once set, you can then enable the IMAP mailbox feature for each user.  (Office 365 customers can skip this step.)  These are the four shell commands:

Set-service msExchangeIMAP4 -startuptype automatic
Set-service msExchangeIMAP4BE -startuptype automatic
Start-service msExchangeIMAP4
Start-service msExchangeIMAP4BE

Step 1: Start two IMAP4 services (and configure those services to automatically start if you wish.)

By default, in Exchange 2013 the IMAP4 service(s) are stopped:

To start those services: On the computer running the Client Access server role:

1. Set the IMAP4 service to automatically start:

     Set-service msExchangeIMAP4 -startuptype automatic

2. Start the Microsoft Exchange IMAP4 service.

     Start-service msExchangeIMAP4

On the computer running the Mailbox server role:

1. Set the Microsoft Exchange IMAP4 Backend service to start automatically.

     Set-service msExchangeIMAP4BE -startuptype automatic

2. Start the Microsoft Exchange IMAP4 Backend service.

             Start-service msExchangeIMAP4BE

In our case, the CAS and Mailbox server roles are on the same box:

Configure Exchange IMAP4 External Connection

This allows users to see (and thus use) the IMAP server.  Here is how via the powershell SET-IMAPSettings cmdlet, e.g.:

     Set-ImapSettings -ExternalConnectionSetting {:993:SSL}.

Note: This requires you restart IIS.

This is true even if you are working within the firewall  Thus in our case, the External Connection is the same as the InternalConnection.

Finally,  Verify things are working, using OWA’s Options select Account, then pick the “Settings for POP or IMAP access” link.

For more information see: http://technet.microsoft.com/en-us/library/bb124489(v=exchg.150).aspx

Enable IMAP for your users
Next, ensure your user mailboxes are enabled for IMAP.
You can do this one-user-at-a-time using the Exchange Admin Center (EAC):

Or via Remote PowerShell for Office 365:

 Set-CASMailbox jimi@sumatra.onmicrosoft.com -MAPIEnabled $True

Which can be set for all users by piping from Get-Mailbox (note that this correctly excludes resource accounts for email migration):

Get-Mailbox -resultsize unlimited ^
  -filter {isResource -eq $false} | set-CASmailbox ^
  -MAPIEnabled $True

#MDaemon calendar to #MSFTExchange Migration Trial

Is available here.

For documentation start with this and look at our other posts.

For email you can use Microsoft's tools. but we've found imapsync more effective.

On-premises @MSFTExchange Migration to #Office365

A PowerPoint Presentation about migrating from on-premises Exchange to Office 365.

The Migration section does not specifically call out calendar migration -- but that's what we specialize in.



Towards the end the notion of a back-out plan is one of the main things we constantly harp on.  Our calendar migration can take Exchange to Office 365 preserving guest lists, responses, and recurrence patterns, and do it in BOTH directions and it includes an UNDO to selectively remove only the data inserted.

DIY calendar process to Migrate @MSFTExchange to #Office365 -- here is the application

The situation: you want to move from Exchange on-premises to the cloud aka Office 365.

You were shocked to discover Microsoft does not have a simple migration solution outside of email.  And the email solution is not even as flexible as imapsync.  All the current third-party tools treat calendaring as an afterthought to email leaving half your calendaring data behind (recurring patterns, guest lists, guest responses).

The result is that post-migration your users see what looks to be their same Outlook/OWA mailbox only to discover that their calendar meetings are broken.

We solved that problem.

Inexpensive solution to better calendar data migration
So we created a calendaring / task / contacts migration process for Exchange on-premises to Office 365  that is an improvement over existing methods in that it gives you more information about guests in meetings (it's an improvement over everyone else if we give you ANY information about guests).

On-premises a meeting looks like this:
                   

Migrated to another Exchange server it will look like this in Outlook with our "flat" option:
                   

Note that we can map user names and resource names and preserve information about attendees outside the domain.

And you can download and try it here with documentation here.  The trial version will insert your appointments for a month into the future.  We're licensing it for $299 for one domain for two weeks.  Based on our MDaemon migrations, we've seen under 1000 user migrations easily accomplished in that time.  If you need more time, ask us.

If you manage your own migration you can get your data in for very low cost with imapsync handling email and our tools handling calendars, contacts, and tasks.

For those of you who want fully-functional calendars post-migration, we offer:
Full-state calendar migration for enterprises with full-state sync.

Contact us for additional details on full-state (though the documentation above is a great place to start).

DIY O365 Migration from Exchange - First Pass

Rarely do we get such an outpouring of "gimme gimme gimme."

So since we're really good at turning out stuff quickly, we've got a first pass at our DIY Guide to Migrating from Exchange to Office 365.  

We have focused on the heavy lifting of migrating email (via imapsync), and calendars, contacts, and tasks (via our tech).

Remember: It's BETA, folks.  You have comments, want additions, think you have something to add, we're really happy to take feedback.  

The other issues: like user provisioning, delegate access, swapping MX records, we've not gone into detail at all since those are pretty well documented on line.  If you need details on how to accomplish this, let us know.

Remember, you'll need to license imapsync.

If you need the calendar, contact, and task migration, drop us a line.

We'll have a simple flat version of our calendar migration software up in a couple of days.

It's simple to run, but unlike everybody else it will tell you who was in your meetings like this:

DIY @imapsync to Migrate Email #Exchange to #Office365 -- We'll add a calendaring process

Your direct costs should never exceed 100 Euros (or $110 at the current exchange rate) for an email migration into Office 365 (From Exchange or any other IMAP server).

imapsync is more than capable of handling your Email migration. Buy the software and support.   

Cards on the table here: we do not get any money from imapsync, but we've found it to be a quality product with a great guy behind it and a good support community.  Add to that it's inexpensive nature and liberal software license and you really cannot go wrong.

You will need to make sure you have permissions on the Office 365 side if you wan to do multiple mailboxes without individual passwords. See our earlier posting on using imapsync to migrate email into Exchange. 

You can also handle migration problems with the wealth of Exchange information in their FAQ:

Pay special attention to the case of read receipts.   Going into Office 365 can re-generate read receipts.  So during your testing if that turns out to be a problem:

imapsync...   --disarmreadreceipts

Other very useful FAQ solutions include what to do when encountering individual attachments over the default limit set by Exchange (10 Mb) and Office 365 (25 Mb), as well as line length issues.

We're working on a DIY document to take you through your own migration.  Frankly, we get lots of questions that could be handled by such a guide.  And we're tired of Microsoft black boxes and over-priced third party offerings.

We'll offer a "flat" calendar migration in an imapsync-like model just so folks can get their migration done if they don't mind a simple calendar migration.  Contacts and tasks are included in this of course.

The goal here is to get your software costs for a migration to Office 365 to under US$1000 with you supplying your own elbow grease.

In rough numbers email, calendars, tasks, and contacts should be about 95% of the data you need to move.