Hi, After some archiving on my mailbox folders, Thunderbird started to ask me to compact folders at every launch of the product, with the same space gain estimate (918MB). I did not check the box to accept the compacting of folders done automatically without asking, because in this situation I consider compacting works badly. I attached a screenshot of the popup window I see. I also discovered that the very same "compact folders" popup window appears everytime I delete mails in some folders. Meanwhile, I can see no error message in Thunderbird that could indicate something turned bad during compacting. So I am currently lost in a "compact folders" loop! Thanks in advance for the help.