We are seeing an issues with Outlook for Mac 2011 and calendar events. These events are in the past and Outlook will randomly post errors about the event stating that it has failed to make changes, please contact the original creator.

Additionally, some users are reporting that Outlook will not successfully send meeting cancellation notices to Windows users. All of the server and directory settings are setup correctly. Is there an issue with Outlook for Mac successfully sending back to the Exchange server here? We're running Exchange server 2007 SP1 and in the midst of upgrading to 2013. Hopefully this and a host of other issues are resolved with 2013. 

Thanks.