Note:

Upon startup, Metropolis Launcher will check if there exists an ml.db file. If it does not exist, it will copy ml.db_initial to ml.db. The ml.db file will contain all your settings and informations about game / emulation files and much more. It should not be overwritten or deleted.

This way you can always update Metropolis Launcher by extracting and overwriting all files from newer zip releases. The ml.db_initial file in future releases will be necessary for database structure updates.

As a safety measure, Metropolis Launcher incorporates a simple backup feature, where ml.db will be backed up in zip files within a backup directory.