The .SIMS3.BAD file was created by The Sims 3 program. The Sims 3 is a game where you create and control simulated people. This file contains game save data that is corrupt. It cannot load properly. You can restore the game from the .SIMS3.BACKUP file. Copy the backup files to another folder first. This way you have backups if you make a mistake. Then delete the corrupt SIMS3.BAD and SIMS3 files in the Saves folder. Remove “.BACKUP” from the backup file’s name. It should now match the name of the deleted corrupt file. You can now load the game again.
The .SIMS3.BAD extension indicates a failed game save for The Sims 3. The creator is Electronic Arts. The file type is a game related file. Currently no software opens .SIMS3.BAD files. Let us know if you find a way to open them.