Unable to open Summary file

[bathcentre]

We keep getting the error: Unable to open summary file for Inbox. Perhaps there was an error disk, or the full path is too long. The disk seems fine (chkdsk's run) and the path to the msf files seems short enough - and anyway the error is intermittent.

Setup: Thunderbird 5. Multiple accounts on windows XP. We use machine logons rather than user logons so any user could be using Thunderbird on any of half a dozen machines, and all mailboxes are available to all users on all machines simultaneously, in effect. There are about 10 inboxes. Local folder is a mapped drive on the server, i.e., Z:\user. Archives are kept in Z:\Archives\user. The drive mapping is to a shared folder on the Windows 2003 R2 server, i.e., //server-name/thunderbird_mail. We are using IMAP direct from each PC to the ISP (i.e., no local mail server).

Mostly, it works. Frequently though Thunderbird seems to slow down tremendously and one or more mailbox, usually on a random-seeming selection of several but not usually all of the machines will give the error "Unable to open summary file for Inbox. Perhaps there was an error disk, or the full path is too long." This happens on trying to open one or more inboxes on the affected machines.

Compacting folders seems to work occasionally. Repairing folders seems to work occasionally. Chkdsk seems to work occasionally. Deleting .msf files seems to work occasionally (but how to find the correct .msf files for one inbox out of 10 I don't know when they are not named according to the user). Copying a clean profile from another machine seems to work occasionally. Doing nothing more than coming in to work the next day seems to work occasionally (really!). In other words, the fixes seem to be random. Deleting a profile and putting it back failed to work. Sometimes the affected inbox's right-click properties will be empty, showing no path, and a default encoding of Arabic rather than Western.

Nice though Thunderbird is, we're thinking of trying another e-mail client if a solution to this cannot be found quickly. Any ideas?

[bathcentre]

No response? It seems this is a quite intractable problem...

[bathcentre]

So far, fingers crossed, the problem seems to have declined or maybe... gone away. I found a configuration error in one user's profile - the user's archive folder was being pointed to the wrong location. After fixing that, and after a couple of days, the problems settled down and disappeared for all users...