I have setup email server for small company whit Ubuntu 16.04, Postfix, (virtual users) Dovecot, Amavis-new, Sieve for Junk mail moving to Junk folder and fetchmail whit fast fetch time (4sec). Two months so far so good, working just fine. Two weeks ago I checked logs as usual for error, spamfilter activity, hackers activity etc and I noticed this error:

Nov 18 16:37:12 server dovecot: imap(mail@server.com): Error: Corrupted index cache file /var/mail/vhosts/server.com/mail/dovecot.index.cache: Broken MIME parts for mail UID 420 in mailbox INBOX: Cached MIME parts don't match message during parsing: Cached header size mismatch (parts=41000000c90b000000000000010c000000000000e7882300000000004cff23000000000003000000410000007a0c000000000000730000000000000077000000000000005b1002000000000066170200000000000700000041000000150d00000000000058000000000000005b000000000000002c2401000000000002280100000000000200000048000000950d0000000000004e00000000000000520000000000000047450000000000002e46000000000000e70000004800000053530000000000004d000000000000005100000000000000cedd000000000000b0e0000000000000e202000040000000c2310100000000007f000000000000008400000000000000401f000000000000a81f00000000000040000000aa510100000000007e00000000000000830000000000000063aa0000000000009aac00000000000040000000b4fc0100000000007f0000000000000084000000000000004907000000000000620700000000000040000000a5040200000000007f0000000000000084000000000000001309000000000000320900000000000040000000600e0200000000007f0000000000000084000000000000003d0600000000000052060000000000004000000045150200000000007f0000000000000084000000000000005907000000000000720700000000000040000000711d020000000000d800000000000000df00000000000000479f110000000000ded911000000000044000000b9bd130000000000dd00000000000000e400000000000000efd50f0000000000960a100000000000a7340000010000000800000096be130000000000eed50f0000000000940a1000000000000000000000000000000000000000000000000000)

(Mail address is changed of course)

Today I checked again and got this error again. Far as I have discovered is that this might be Dovecot bug whit Sieve. Do anyone have experience whit this? Can this result in mail corruption? I have found cases where email client is causing it. Far as I know Outlook (I don't know version) and iphone is used.


For index caching, it should be enough to stop dovecot, rename the corrupted file (ie. dovecot.index.cache.old) and restart dovecot.

This is valid for cache file only. Do not delete other files and always do backups before modifying anything.

  • I consulted folks at irc and they suggested the same. I did, but it it too early to tell if it helped or not. – Maigonis Nov 29 '17 at 19:35
  • It didn't helped. Error after a while is back. Any other suggestion? – Maigonis Dec 11 '17 at 16:26

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.