A week ago for some reason that I don't recall a window appeared to the effect that the filters for mail to the folder "inbox" subfolder "me" would be inactivated. The next day I added the "x" to that filter, and the same the following day. The third day, all filters were missing and the msg filters file was reduced to 1kb.
Today copied the msgfilter file from a backup thumb drive (14kb) and all is fine.
In years of using TB & prior nuances have never had this occur on the desktop. Question what causes this and how to prevent it in the future.