A BAK1 file is a backup file used by Starbound, a 2D space exploration game. It stores backup information for the game, such as details about a player character or spaceship. BAK1 files are helpful for recovering information in the event of a computer crash or corrupt PLAYER or SHIPWORLD file.

BAK1 files bear a compound file extension. The ".bak1" extension is added on to a file that it is storing information for. For example, if the file is storing backup information for a PLAYER file, the filename would be ab 07704dbcb4162646d4d93bbeef34df.player.bak1. You can delete the ".bak1" extension from the filename and open the file as a PLAYER file in Starbound. However, it is important that you do not change the string of characters preceding the extensions. BAK1 files can be found in the "player" folder in the "Starbound" folder. For example if you purchased Starbound through Steam, the BAK1 files are stored in the following location in Windows: C:/Program Files/Steam/SteamApps/common/Starbound/player NOTE: Starbound also uses .BAK2 and .BAK3 files.