I've deleted some empty IMAP folders, using Thunderbird. But before deleting them, I had a look into Trash directory on the filesystem:

/home/pvo/mdbox/mailboxes/Trash/ ├── dbox-Mails │ ├── dovecot.index │ ├── dovecot.index.backup │ ├── dovecot.index.cache │ └── dovecot.index.log ├── Dev │ └── dbox-Mails │ └── dovecot.index.log ├── S4 │ └── dbox-Mails │ └── dovecot.index.log └── Server4 └── dbox-Mails └── dovecot.index.log

(Yeah, looks good, no dbox-GUID file.)

After deleting all IMAP folders from Trash I found this lines in the log file:

Apr 06 05:44:36 imap(pvo): Error: file_dotlock_open() failed with file /home/pvo/mdbox/mailboxes/Trash/S4/dbox-Mails/dovecot.index.log: No such file or directory Apr 06 05:44:36 imap(pvo): Error: file_dotlock_open() failed with file /home/pvo/mdbox/mailboxes/Trash/S4/dbox-Mails/dovecot.index.log: No such file or directory

Regards, Pascal

The trapper recommends today: fabaceae.1009606@localdomain.org