Yep I have seen this same issue, and in all cases, I have suggested for the users to run SCANPST.exe and once it's complete, the local cache is almost always the culprit. It's especially
noticeable when the users have large (in excess of 10 gig) mailboxes.
This is exacerbated when Admins who will have several VIP mailboxes opened in her client.
This all points to .OST corruption, or at least adding to this sort of issue.
Using OWA always shows current and accurate information, and switching from cached mode to non-cached mode, likewise shows correct info.
Users are reliant on cached mode and autodiscover, so disabling these is not an option.
But for those dealing with this issue, do try the SCANPST, or, close Outlook and delete the OST and force Outlook to download. This option usually works.... for a while. :)
i think it's still not too late to dig to this issue. As i am having the same problem here in the office. our staffs here are around 120, we are using Exchange 2010 and all users are using Outlook 2010. almost half of the staff are having issues with their
calendar not updating unless you close it or uncheck the cache mode in outlook, which is not a good idea.
i was quite surprise that until now, after all the search i did on the internet there were no permanent fix for this issue. I also need help/assistance with this.
here are the thing i did so far:
-recreated the profile
-scan pst done
-re-add the shared calendars (resources and shared users calendars)
- disable the cache mode in Outlook 2010 (this fixed it, but i do not consider this as a permanent resolution)
i do not know which one to check or settings to double check from our Exchange. Running out of ideas. And aside from this, we are also having issues with double booking with resources (allow conflicts of course is not checked)
Hope you guys can spare some light on this matter. TIA!