the addition of an .MSF file extension would indicate that Thunderbird has read is into a folder, but and this is the important part, you should not have a .mbox extension on the files if Thunderbird is to use them for folders.

My wild and unsubstantiated guess is you ant virus has found something in the file it did not like and has quarantined it. This is very common with old mail files as things that were not considered a threat way back when are not flagged as such. Most anti virus products when allowed to automatically fix these issues simply quarantine or delete the file in question, not the individual mail.

the addition of an .MSF file extension would indicate that Thunderbird has read is into a folder, but and this is the important part, you should not have a .mbox extension on the files if Thunderbird is to use them for folders. My wild and unsubstantiated guess is you ant virus has found something in the file it did not like and has quarantined it. This is very common with old mail files as things that were not considered a threat way back when are not flagged as such. Most anti virus products when allowed to automatically fix these issues simply quarantine or delete the file in question, not the individual mail.

thanks for your reply, Matt! I checked my virus vault and see no evidence of my .mbox file there unfortunately.

UPDATE: i found a backup of my .mbox file that i had forgotten about and was able to use it to recover the data i needed. my problem is solved! PLEASE REMEMBER TO BACK UP THE THINGS YOU NEED SO YOU DON'T END UP IN A PANIC LIKE ME

for other users , more info on Contacts, Address-Book,etc: • Convert MAB/mork or SQLite based Address-Book into other format , MBOX (combined)-email files into other format.