The autosave feature stores the edited osm layers and Notes layers in regular interval so that the work can be recovered in case of a crash.

Recover the changes

You simply need to restart JOSM and it will offer to open the recovered files.

You can also find the backup files in the JOSM preferences folder (subfolder autosave), where JOSM stores them.

See Help/Preferences page on how to locate the preference folder.

Prompt after JOSM start

User will be asked to restore or discard latest snapshot from autosave.

If user chooses to discard, there no change to recover work again.


  • How does it know that JOSM crashed?

It keeps backups that are deleted, whenever a data layer is closed gracefully. If backup files are found on start, JOSM will assume that it crashed.


Go to source:trunk/images/preference.png Preferences -> source:trunk/images/preferences/map.png map projection & data interpretation -> tab "File backup"

AutoSave preferences dialog screenshot

There you have these options:

  • disable autosave altogether
    • set a custom value for the time interval in seconds (default is 300).
    • set a custom value for the number of backup files per data layer (default is 1). If you increase it to 2, JOSM will not only save the last snapshot of your changes, but also the last but one (in case it differs from the last, otherwise an even older snapshot, if available).
  • keep backup files when saving data layer: JOSM can keep a backup file when saving data layers. A "~" is appended to the file name and it is saved in the same folder.
  • Choose if you want to see a small notification at each save.

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Last modified 15 months ago Last modified on 2017-11-12T12:26:48+01:00

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