Quick Fix for Dovecot’s “save failed to INBOX: Timeout while waiting for lock”

I had a mail server lock up and die on me tonight. The data center replaced some hardware in order to get it to power back up. Everything started up fine, but I was unable to retrieve my own email. My mail client was complaining about timeouts on a single account. In looking at the log, I found some lines similar to these in the dovecot mail logs:

Jul 13 04:19:09 secure deliver(user@domain.com): msgid=<20110713105301.E4C2C3293DC@myserver.com>: save failed to INBOX: Timeout while waiting for lock
Jul 13 04:19:09 secure deliver(user@domain.com): msgid=<20110713105702.817483293E5@myserver.com>: save failed to INBOX: Timeout while waiting for lock
Jul 13 04:19:09 secure deliver(user@domain.com): msgid=<20110713105802.3F68E3293E7@myserver.com>: save failed to INBOX: Timeout while waiting for lock
Jul 13 04:19:09 secure deliver(user@domain.com): msgid=<20110713105402.B5DBA3293DE@myserver.com>: save failed to INBOX: Timeout while waiting for lock
Jul 13 04:19:09 secure deliver(user@domain.com): msgid=<20110713102202.6045E3293A6@myserver.com>: save failed to INBOX: Timeout while waiting for lock

Googling the error message didn’t find any quick results, so I attempted a more brute-force method. Inside the user’s maildir, I just moved some dovecot files out of the way:

[root@host /vmail/domain/user/]# mv dovecot-uidlist.lock dovecot.index dovecot.index.cache dovecot.index.log /tmp/badfiles

After moving those files out of the way, I restarted dovecot with

/etc/init.d/dovecot restart

and my client was able to connect without problems.