I debugged my imap connection. The imap log shows the next message error:
[24-Jun-2011 12:52:53 +0200]: S: * BYE [ALERT] Fatal error: max atom size too small: No such file or directory
[24-Jun-2011 12:53:01 +0200]: S: * OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA ACL ACL2=UNION XIMAPPROXY] Courier-IMAP ready. Copyright 1998-2010 Double Precision, Inc. See COPYING for distribution information.
To reproduce the problem:
- I go to the Sent folder (I have more than 10.000 e-mails);
- I use the search engine and search for something that the result is greater than 5000;
- Select all the mails and attempt to move a folder and then the error appears;
I use courier-imap without SSL.