Filext says it's probably an "email data file." There are a couple of other possiblilies given, but none that you're likely to have. If you have any kind of "contact manager," as a separate program or embedded in a browser or email program, that would be the most likely source for the file.

It's most likely a database format, and sometimes they fail to defrag if the database hasn't been "compacted" recently. Edits to a db sometimes leave unlinked records that are "deletion pending" and the defrag may be afraid to move them without knowing how they fit into the database.

This isn't a filetype that I recognize as part of my email system, but may be a standard type for one of the other browsers/email programs.

It's possible that the filetype is registered in Windows (so that Windows knows what to open it with if you click on the file). Looking in the filetypes setup might give a better clue than the generic answers at Filex.

John