Automatic Backup (.sav and .bak) and Autosave

The autosave and backup features is available since JabRef 3.7.
To reduce the amount of configuration options, the possibility to disable the creation of .bak files was removed in JabRef 5.1.
JabRef generates .sav and .bak files while working. .sav is the automatic backup feature: Each 15 seconds, the current state of the library is saved. .bak preserves the last state of the library after saving. Thus, one can go back one save command in the history.
By using the gitignore.io service, you can generate an appropriate .gitignore file by opening https://www.gitignore.io/api/jabref.
In addition to .bak and to .sav, JabRef offers automatic saving of the library. No need to click on File --> Save or pressing Ctrl+S anymore: The opened database are saved automatically without manual intervention.

Automatic saving of the current library

In case the .bib file should automatically be saved on each change, you can direct JabRef to do so. This feature needs to be activated in the preferences:
Screenshot of the autosave preferences

Automatic backup of current library edits

This functionality runs in the background while you are working on a bibliographic database. It makes a backup copy (in a .bib.sav file) and keeps that up-to-date on every user interaction. For instance, when you change a field the new value would get saved into the backup copy. Assuming that JabRef crashes while you are working on a BibTeX database. When you try again to open the file JabRef crashed with you will get the following dialog:
Screenshot of the backup dialog
Now you have the possibility to restore your changes which would normally get lost.
When JabRef gets closed normally the .sav file will be removed. Otherwise, this file is going to be used for database restoration next time.

Backup of last library version

The .bak file preserves the last state of the library before saving. Thus, one can go back one save command in the history. For more advanced history, we recommend to use git as version control system.