I am running cyrus-imapd-1.6.24 along with postfix under Red Hat Linux 7.0 on a li'l old i386. Most of the time it works flawlessly, but occasionally a delivery dies with a log entry like the following: Feb 15 15:03:46 heidegger deliver[8181]: checkdelivered: error opening delivered database: /var/imap/deliverdb/deliver-j.db: Resource temporarily unavailable This only occurs when a mail is being sent to multiple local users. The mail is actually successfully delivered. A web search revealed that several sites had experienced "Resource temporarily unavailable" errors associated with a failure to fork, and were able to fix them by increasing the allowed number of user processes. But my error says nothing about a failure to fork, and I have not set any limit on the number of user processes. Can someone suggest what might be going on and how to fix it?