Our users have always stored their PST files on a mapped network drive and all was going well until about a month ago.
In the last month, we've had a rash of users complain that when they try to open their PST files, they get an Outlook message box "Unable to expand the folder. The set of folders could not be opened. The file [filename] is in use and could not be accessed..."
In general, when the user logs off of Outlook, the PST file becomes available once again. Sometimes, the user needs to log off of the network and log-back in to regain access to their PST. These users are not logged on to any other computers and only the specific user (and the IT team) has rights to the folder containing the PST--so we don't think anyone else has an open copy of these PST folders.
Has anyone else seen any similar locking behavior with PST's saved on a network or any ideas for what to look at?
(Microsoft does advise against saving PST files on the network--but why would this behavior have just begun having an effect on our users? In any event, we need to back-up the PST's and it's far easier to do that on the network than on local hard drives).