SOLVED: Outlook Error ‘Cannot send this meeting request. The property does not exist.’

If you modify an Outlook Calendar event, click SEND UPDATE and then see: Cannot send this meeting request. The property does not exist.  Your meeting likely has some hidden attachments

Download MFCMapi.exe from http://mfcmapi.codeplex.com

1. Un-zip the file and click on the mfcmapi.exe
2. Click Session
3. Select Logon and Display Store Table
4. Select the mailbox
5. Expand Root
6. Select IPM_SUBTREE
7. Select Calendar
8. Click on the Subject header to sort by subject
9. Locate the meeting request
10. Verify that Att? header = True
11. Double click on the meeting, which will open the  meeting request, and verify the attachments it has if any
12. Close the meeting request
13. Right click on the meeting and select Display Attachment Table
14. Delete the attachments from the list except for the attachments you noticed in the meeting request
15. Restart Outlook

This was taken from: http://social.msdn.microsoft.com/Forums/en-US/outlookdev/thread/1d4a2c31-6b01-4b68-aea7-943a0f2b732e 

You may also find this post useful: http://social.technet.microsoft.com/Forums/en-US/exchangesvrclients/thread/41f17ad7-11f8-493a-aa46-616ccef4fbfa