You might want to clear Thunderbird IMAP cache due to some reason. I just tried to clear my Thunderbird cache due to some privacy issue as it cache my email content on the public machine. To prevent Thunderbird from auto cache all your the IMAP email at your local machine, you need to disable the sync option for your IMAP account.
To clear Thunderbird IMAP cache, follow the steps below:-
- First, start your Thunderbird
- Go to Tools -> Account Settings -> Select “Server Settings”
- Highlight and Copy “Local Directory” path
- Close your Thunderbird now.
- Paste the path to Window Explorer, now you should see a list of files.
- Highlight all the file EXCEPT msgFilterRules.dat and delete all.
- Now start your Thunderbird again, your IMAP cache should be removed by now.


