EssentialPIM’s backup files are saved in either of the following formats:
These are the valid database files that can be opened in EPIM (rename *.epim.bak to *.epim before opening such files).
By default settings, backups are made automatically every 24 hours in the folder where your EPIM database file is located. To adjust the backup settings to your needs, click on Tools->Options->Backup.
More info about backup and backup file types can be found in the Backup section of the help file.