Hi, I use Thunderbird (38.2). Thunderbird keeps hiding / deleting my mails, and I would like to know what happens and how to make it stop. I have 3 e-mail accounts connected: 1 POP3 and 2 IMAP (let's call them A and B). 4 weeks ago, all of my mails of my first IMAP account A in personal folders disappeared, both at Thunderbird as well as on the server, while my mails in Inbox, Sent, Drafts were still there. At first I suspected problems with my e-mail provider, as my account B seemed fine (though I do not have personal folders there, which may explain that). However, today I received two mail to my second account B (other provider), and while I was answering, they both disappeared ! They were neither in Junk nor bin, nor on the server anywhere to be found. While doing the list of http://kb.mozillazine.org/Disappearing_mail to retrieve my mails, I found that most of my mails of account A are in the AppData\Roaming\Thunderbird\...\A directory. Happy surprise! There are always 2 files per folder: MyFolder and MyFolder.msf. If I open MyFolder with notepad, I can see my mails. Now I tried to do "Properties/Repair" of one folder, which resulted in MyFolder being deleted and a fresh MyFolder.msf and the mails gone. Yay! Maybe previous repair attempts resulted in other folders being already non-existant. So my first question: Why did my folders go blank (eventually my .msf got corrupt) and how do I get my mails back to show in Thunderbird? I tried closing Thunderbird, deleting msf, restarting with no success. Secondly, however, the mails of account B which went missing this morning are still missing. I remember the text and searched in AppData\Roaming\Thunderbird\...\B with nothing to be found. I use Windows 7 and Microsoft Security Essential as antivirus, and it doesn't show anything as quarantined. Any ideas that could help a desperate soul?