They've stopped receiving new mail in the inbox on the laptop, however their Black Berrys are still receiving mail normally.
When I disable outlook's cached mode and restart outlook their inbox populates normally with all emails.
I have found that sometimes a move can help solve these weird anomalies.
I have foudn that even just login into the OWA/OWAP webmail fixed some issues.
What issues do you forsee if I was to try exporting the user's entire mailbox to a .pst, removing their store on the exchange server, recreating the store, then importing the pst file to recreate their email/calendar/addressbook If you copy everything to a pst and make sure it has everything that you need (don't forget contacts and calendar).
I've tried to enable Cached Exchange Mode but no advanced options are available in my version of Outlook 2016--it's not even greyed out, it's not available at all.If I turn cached mode back on and restart outlook it goes back to the same point in time when the emails originally stopped arriving.All emails after that point are no longer in the inbox. I checked the files and they are both different sizes and less than 1GB.I've disabled the antivirus on the server, now when I opened the mail file it only populates to January 30 2007.I've effectively lost even more emails in cached mode.