Having an empty m-File, doveadm force-resync isn't able to detect and
repair this:
-rw------- 1 vmail vmail 4948043 8. Jan 20:32 m.634
-rw------- 1 vmail vmail 5237411 8. Jan 20:32 m.635
-rw------- 1 vmail vmail 0 9. Jan 16:23 m.636
mail1:~ # doveadm force-resync -u user mailbox INBOX
doveadm(user): Warning: fscking index file
/vmail/example.com/user//mdbox/storage/dovecot.map.index
doveadm(user): Warning: mdbox
/vmail/example.com/user//mdbox/storage: rebuilding indexes
doveadm(user): Error: Corrupted dbox file
/vmail/example.com/user//mdbox/storage/m.636 (around offset=0):
EOF while reading file header
doveadm(user): Error: mdbox rebuild: Failed to fix file
/vmail/example.com/user//mdbox/storage/m.636
doveadm(user): Error: mdbox
/vmail/example.com/user//mdbox/storage: Duplicate GUID
2cafdd2f0224ec50773c0000085c1439 in m.627:16 and m.638:16
Peer
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