Outlook crashes/freezes opening shared calendar appointments for specific user

Hi there

We have an issue that seems to be related to a single users calendar.

When opening their shared calendar and trying to change/edit appointments Outlook is very slow to respond and will regularly crash or hang.

It only happens for this particular user and it seems anyone who opens this shared calendar has the problem. All other users shared calendars I have tested seem fine and behave as normal.

Running Office 365 Business (local install) and Exchange 2013.

Sometime (not every time - fairly rarely actually) some errors appear:

" Sorry, we’re having trouble opening this item. This could be temporary, but if you see it again you might want to restart Outlook. The file you're attaching is bigger than the server allows. Try putting the file in a shared location and sending a link instead."

and

"Cannot save this exception to a recurring appointment, meeting, or event.  Close the items and try again. You don't have appropriate permission to perform this operation."

Permission are OK for the users and there are no attachments so I am not sure what these errors mean?

I have checked the number of items and calendar folder size in Exchange Console (Get-MailboxFolderStatistics) and it looks OK. I have compared it to other users whose shared calendars are fine.



Any advice would be great



Thanks