On 25.3.2013, at 16.22, Gordon Grubert <gordon.grubert+lists@uni-greifswald.de> wrote:
Mar 25 15:08:46 mailserver2 dovecot: imap-login: Login: user=<USER>, method=PLAIN, rip=IP, lip=IP, mpid=28663, TLS, session=<In7mV8DYFQCNNQQ4> Mar 25 15:08:46 mailserver2 dovecot: imap(USER): Error: Cached message size smaller than expected (2252 < 4821) Mar 25 15:08:46 mailserver2 dovecot: imap(USER): Error: Maildir filename has wrong S value, renamed the file from /var/vmail/uni-greifswald.de/USER/Maildir/cur/1169635911.30322.scooby,S=2252:2,RS to /var/vmail/uni-greifswald.de/USER/Maildir/cur/1169635911.30322.scooby,S=2252:2,RS .. The same problem was reported by Ralf Hildebrandt one year ago. The bug should be fixed with revision 3599790da3d7 but it seems to be there again.
The Dovecot bug was fixed, but the real reason for this is that the S=values are wrong in your maildir. You can either run the fixing script or set maildir_broken_filename_sizes=yes.
Input/output errors of the file system are improbable because all files are accessible and can be read with cat and less.
That's just Dovecot's internal way of passing a failure to other parts of the code.