I have the same problem related to the thread "idle pop3d never times out" with Cyrus 2.0.16. A user has closed his pop3 client in the middle of downloading the mails with W2000 and OE. The following times the user has tried to download his mail the server has responded "IN-USE...", and after reboot his machine the situation has not changed, and 10 hours later... equal.
In the server when I execute: # lsof -i | grep pop3 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME pop3d 1512495 cyrus 0u IPv4 0x48346140 0t0 TCP srv-du-ops2-dmz5.datadec-online.com:pop3->116.red-213-0-70.pooles.rima-tde.n et:2179 (ESTABLISHED) pop3d 1512495 cyrus 1u IPv4 0x48346140 0t0 TCP srv-du-ops2-dmz5.datadec-online.com:pop3->116.red-213-0-70.pooles.rima-tde.n et:2179 (ESTABLISHED) pop3d 1512495 cyrus 2u IPv4 0x48346140 0t0 TCP srv-du-ops2-dmz5.datadec-online.com:pop3->116.red-213-0-70.pooles.rima-tde.n et:2179 (ESTABLISHED) pop3d 1512495 cyrus 4u IPv4 0x4162c000 0t0 TCP srv-du-ops2-dmz5.datadec-online.com:pop3 (LISTEN) After waiting for a time I kill the 1512495 process and all is OK and the user return to work again. There is any type of solution to this problem? Is solved upgrading Cyrus? Greetings and thanks... Sebastian Calero Datadec Online.