Hi everyone I have 3.1.0_GA_260.DEBIAN3.1 just upgraded from GA 197 which had the same problem by the way. The problem I have as the title suggests, every so often the MTA and Mailbox services stop and leave the following in the log.

2006-03-30 11:40:50,254 INFO [Timer-0] [] stats - 03/30/2006 11:40:50,,,,,,8,0.50,,,,,,,,,,,,,,58.111,0,19,6,2, 505,94,,0,0,0,0
2006-03-30 11:41:01,996 INFO [main] [] StatsImageServlet - Servlet StatsImageServlet shutting down
2006-03-30 11:41:01,997 INFO [main] [] soap - Servlet AdminServlet shutting down
2006-03-30 11:41:01,997 INFO [main] [] TcpServer/7025 - LmtpServer initiating shutdown
2006-03-30 11:41:01,998 INFO [LmtpServer] [] TcpServer/7025 - finished accept loop
2006-03-30 11:41:02,006 INFO [main] [] TcpServer/7025 - LmtpServer shutting down idle thread pool
2006-03-30 11:41:02,006 INFO [main] [] TcpServer/110 - Pop3Server initiating shutdown
2006-03-30 11:41:02,008 INFO [Pop3Server] [] TcpServer/110 - finished accept loop
2006-03-30 11:41:02,008 INFO [main] [] TcpServer/110 - Pop3Server shutting down idle thread pool
2006-03-30 11:41:02,009 INFO [main] [] TcpServer/995 - Pop3Server initiating shutdown
2006-03-30 11:41:02,009 INFO [Pop3Server] [] TcpServer/995 - finished accept loop
2006-03-30 11:41:02,009 INFO [main] [] TcpServer/995 - Pop3Server shutting down idle thread pool
2006-03-30 11:41:02,009 INFO [main] [] TcpServer/143 - ImapServer initiating shutdown
2006-03-30 11:41:02,010 INFO [ImapServer] [] TcpServer/143 - finished accept loop
2006-03-30 11:41:02,010 INFO [main] [] TcpServer/143 - ImapServer shutting down idle thread pool
2006-03-30 11:41:02,010 INFO [main] [] TcpServer/993 - ImapSSLServer initiating shutdown
2006-03-30 11:41:02,010 INFO [ImapSSLServer] [] TcpServer/993 - finished accept loop
2006-03-30 11:41:02,011 INFO [main] [] TcpServer/993 - ImapSSLServer shutting down idle thread pool
2006-03-30 11:41:02,022 INFO [main] [] SessionCache - shutdown: clearing SessionCache
2006-03-30 11:41:02,022 INFO [IndexWritersSweeper] [] MailboxIndex - IndexWritersSweeper thread exiting
2006-03-30 11:41:02,022 INFO [main] [] MailboxIndex - Flushing all open index writers
2006-03-30 11:41:02,058 INFO [main] [] RedoLogManager - Logged: 24 items, 2.958ms/item
2006-03-30 11:41:02,058 INFO [IncomingDirectorySweeper] [] FileBlobStore - IncomingDirectorySweeper thread exiting
2006-03-30 11:41:02,059 INFO [main] [] extensions - Destroying extensions
2006-03-30 11:41:02,250 INFO [main] [] extensions - Destroyed extension clamscanner: com.zimbra.clam.ClamScanner@com.zimb...tensio n.ZimbraExtensionClassLoader@18041e0
2006-03-30 11:41:02,250 INFO [main] [] ContentServlet - Servlet ContentServlet shutting down
2006-03-30 11:41:02,251 INFO [main] [] PublicICalServlet - Servlet PublicICalServlet shutting down
2006-03-30 11:41:02,252 INFO [main] [] soap - Servlet SoapServlet shutting down
2006-03-30 11:41:02,252 INFO [main] [] account - Servlet PreAuthServlet shutting down
2006-03-30 11:41:02,253 INFO [main] [] mailbox - Servlet UserServlet shutting down
2006-03-30 11:41:02,254 INFO [main] [] FileUploadServlet - Servlet FileUploadServlet shutting down

I Have checked for any cron jobs that run at those times but still no success. If anyone wants more information on this problem just ask. Thanks.