After upgrading Office 2010 to Office 2013, we have a user who has an issue with viewing the details of a specific shared calendar. Randomly, when the user double clicks on a calendar event to view the details of it,  she is given the error of not having permissions to view it. I noticed that when she goes to click, it looks like the mouse ignores the event and tries clicking onto the calendar itself (which is underneath the calendar).

They currently have Reviewer permissions.

I have tried the following:

-Renamed .ost to ost.old, and recreated ost

-delete/ readd calendar

-Run Offcat- did not find any calendar issues

-Ran a repair on Office

-Gave the user full permissions to calendar. All this did was pop up blank calendar events when she clicked on the calendar.

-Gave myself the same permissions to the calendar. Had no issues viewing details.

Hi,

According to your description, I understand that user access shared calendar with permission error after upgrading Office 2010 to Office 2013.
If I misunderstand your concern, please do not hesitate to let me know.

How about the OWA? Ensure all client or some special account experience this issue.

If the users can view shared calendar in Outlook Web App (OWA), it indicates that the user already has the correct permission. Please try to disable "Download shared folders" function or switch to online mode for testing, for your reference:
1. Open Outlook, goto File > Account Settings > Account Settings
2. Select your Exchange profile > Change > More Settings > Advanced tab
3. Check Use Cached Exchange Mode (if not already checked)
4. Uncheck Download shared folders
5. Click OK > Next > Finish, and restart Outlook

Thanks