Purpose of mail_dat.dat-bak file?

I backup my em Client files to my Google Drive. I would prefer to save the bandwidth required to backup the mail_dat.dat-bak file. I checked this forum for details about this file but found nothing so I closed the program, moved the file and reopened em Client - the world did not come to an end, everything appears to be OK. So what is the purpose of this file?


The bak file signifies that is it a backup for database reconstruction purposes, most of the time it gets created when eM Client checks for database corruption after an improper shutdown and attempts to repair it. Under most circumstances eM Client will run without a problem if you remove the file. I’d still advise backing it up however.