The Berkeley Studio makes automated back-ups of your project, each time you save, a backup is made. These are stored in the subfolder history of your model - which is automatically made when you create a new model. You can revert to an earlier version of the model by choosing
[File > Revert]. This will open open a pop-up window with an overview of all back-ups. Any document added to your model are also saved by this mechanism.
Revert to a chosen back-up by pressing
[OK]. The backup will be moved from the backup folder and will overwrite the current model. Note that if there are more than 600 backups, the Berkeley Studio will remove half of the last 200 backups, so you may not always have as many backups.