Three times within six months, the inbox in my wife's Thunderbird email has emptied, without warning. While writing a message, her work and all read and unread email in the inbox has simply vanished. All other folders have remained intact.
I have not had the same problem. We both have Windows 7 64-bit in Intel Core 2 systems, mine perhaps a bit more robust but basically similar.
A dozen or more posters to a Thunderbird support forum have reported the same problem. Remedies have been suggested, but all have failed. Just thought I'd try here....