In MobileAsset v7's Database Manager, the location of the backup file is set on the Backup tab, at the lower left. At a new installation, this location shows <Default SQL Server Location>, which results in a filename of "WaspTrackAsset_yyyymmdd_hhmmss.BAK" (with the date & time values specified automatically).
However, if this location is changed by the user, the full filename must be specified by the user every time, and the date & time are not automatically set.
How to revert this location back to the default:
If it's open, close Database Manager.
In Windows File Explorer, browse to the following path (use the appropriate username and random characters from your installation):
Edit the user.config file in Notepad or other text editor. Delete the BackupLocation path that appears between <value> and </value> (see screenshots below). Save the file.
Reopen Database Manager. The backup file location should be <Default SQL Server Location>.