I'll admit this is slightly convoluted AND bad user behavior, but we can do this using standard, completely legitimate commands. This makes us leery about what other methods remain to be discovered.
So first let's look at my calendar:
Three meetings each with Conference Room 222 already reserved.
Highlight the one at 10:00 AM and press DELETE. This dialogue box displays:
NOW for the deviltry. If you press "Send" right now everything will be hunky-dory and the meeting will be cancelled cleanly. But let's not.
Instead, let's say that you DELETE the conference room AND add "zyg" as a required guest:THEN hit SEND. In Zyg's calendar we see the meeting has been cleanly deleted.
Aside: Adding "zyg" is a crucial step. If you try to send without a Required user you get an appropriate warning.
Anybody care to guess what the calendar for Conference Room 222 looks like? Right. The meeting is still in there.
Kudos go to Russ and the insertion team for discovering this.So ends Part I: Creating the broken meeting. Watch this space to see how you can find and remove the broken meetings.
Note that KB 954284 Outlook 2007 does not send out meeting cancellations if you remove all invited attendees from a previously created appointment describes a similar situation using Outlook 2007 rather than OWA.