PCBnew difference between Rescue and Revert to Last Backup

“Rescue” seems to want to load a file called _autosave-projectname.kicad_pcb. I saw this file briefly when I opened a project that had crashed, but it disappeared after opening the normal .kicac_pcb file. I have found the option in pcbnew settings to set the autosave time interval.

1* So autosave does not actually save to you .kicad_pcb file, it saves to a different file that disappears if you don’t know how to handle it?

“Revert to Last Backup” wants to load a file called projectname.kicad_pcb-bak. I have not found any setting or description on how, why or when this file is made.

2* How is the backup files generated and how do I setup the function?

3* What is the preferred one of the two options, why do they co-exist?

Hello @HSPalm-

  1. Autosave exists to restore your work if KiCad crashes. So when you successfully save the file, we remove the autosave file.
  • Note that there was a bug in 5.1.0 that prevented detecting the autosave file. That has been fixed in 5.1.2.
  1. The backup is simply a copy of the previously saved file. Reverting to the last backup goes back to the previously saved version of your work.

  2. The autosave is useful if you haven’t pressed save since you did work on your board and the program crashed. The backup is useful if you did save but you wanted to go back to a previous revision and undo all of the saved changes.

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Personally I do not like to rely in any way on “autosaved” or auto generated backups.

Instead I make plenty of intermediate backups myself.
Wen I’m working on a serious project, at least once a day, but when I’m working with some software that is particulary unstable I’ve had times that I made backup copies upto 5 or 6 times a day.

The biggest advantage is that if you use your own backup scheme you are not dependent on whatever the software you’re useing today has implemented as backup and it works with any program that generates files on a computer disk.

It must have been about 30 years ago, Once I got bitten very badly by a very badly implemented “autosave” feature, that overwrote the original project files regularly.
So I had an experiment, after a few hours decided that the experiment did not work and wanted to revert to the original files, but those were overwritten by the autosave feature. The result was a few days of lost work.

After that I’ve been disabling any autosave feature in every program I use for … a long time, but now I simply do not care anymore, because I rely on my own backups.

Making such backups can be as simple as making a zip archive of the whole project and pre-pending it with a date in ISO8601 format. So, then after a wile you have project names like:


Some of these backups with particularly nteresting milestones get saved to external media, most are simply dumped in a backup directory and fogotten. (But I do sometimes find myself sometimes sniffing around in 6 or more years old backups for various reasons.

There are more elaborate (and in a lot of ways better) methods for backups, (Such as for example GIT, or specialised backup software. The big advantage of this method is the extreme simplicity. Anybody with a bit of computer knowledge can do it in a minute or so.

  1. Okay, I am on 5.0.2. Thanks for explaining. I will upgrade and try to recreate the problem, because I surely did not save anything when the autosave file disappeared. I simply opened the .kicad_pcb file.

Couldn’t autosave simply be an automated CTRL+S every set interval instead of using a separate file to restore and delete? It is at least what I would expect from it.

Thanks for sharing. I usually work in a Google Drive synchronized folder, all my projects rely withing Google Drive. If I need to restore something I can look through the history and restore every single change. Of course this is a paid service, I don’t know if you get any useful storage for free these days. It’s also dependent on an internet connection, I believe(?).

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