Whenever I attempt to retrieve or delete mail (Using thunderbird win client) operation takes several minutes. right before completion posts the following error to maillog:

May 14 10:22:04 NAPUtil imap(djrobert): Timeout while waiting for release of shared fcntl() lock for index file /home/djrobert/Maildir/.Trash/.imap.index

deleting the index file speeds up the operation once. subsequent operations are slow again

I don't know what other process is placing a lock on the file. or how to clear it.
I am running the 9914p0 package distributed with a march 11 3.7 snapshot (OS loaded from the same snapshot). I previously was running the release 3.6 OS and the Dovecot package that came with the CD. both installs exhibit the same behavior.

Both Dovecot and postfix are configured with fcntl locking only.

What the heck am I doing wrong?

Thanks,
Dale