Is the date/time setting correct on client site?
I have never used Cozi product, but if it exists as Outlook add-ins, please try to disable it to check if the data/time issue still persists.
At this point I suggest that we may create a new Outlook profile, launch Outlook with safe mode and then re-setup the user's account setting to re-sync his mailbox.
How to create and configure email profiles in Outlook:
http://support.microsoft.com/kb/829918/en-us
Start Outlook with safe mode. ("Outlook.exe /safe")
If you are in Exchange environment, we may use CalCheck tool to collect more information for further troubleshooting.
http://support.microsoft.com/kb/2678030/en-us
Thanks.
Tony Chen
TechNet Community Support
"Is the date/time setting correct on client site?"
First question I asked Help Desk to check. This CalCheck tool looks interesting. Never used it before. Does it just do checks on the Calendar? It doesn't try to "fix" anything, does it?
Thank for your interesting.
Yes, the CalCheck just performs various checks on general settings, such as permissions, free/busy publishing, delegate configuration, and automatic booking. However, this tool would not fix anything for calendar but only return a report.
Tony Chen
TechNet Community Support