Fusion
I was working on a previously saved project for a couple of hours when my Windows 10 crashed (blue screen).
After my PC rebooted, I launched Fusion 360, but the Recover Documents dialog did not show up.
I navigated to %AppData%\Roaming\Autodesk\Autodesk Fusion 360\<GUID>\CrashRecovery to find a .backup file that was last modified just minutes ago with a reasonable size (~190 MB).
I created a copy, changed the extension to .F3D and tried to open it in Fusion 360 - however, the archive was corrupted.
Upon further inspection with a Hex Editor, I noticed that the file content was abruptly cut of after the 335th byte and what followed were approximately 189'266'569 NUL characters:
To my annoyance I came to realize, that there was only a single .backup file of this project - although supposedly Fusion 360 automatically creates a recovery backup every 5 minutes.
It turns out, that the .backup files are overwritten (!!!) whenever a new backup is created.
Mind-boggling! Who in their right minds thought this was a good implementation of an auto save system?!
At the very least, rename the previous .backup file, create the new .backup file and, only once it is created successfully, delete the previous .backup file.
Ideally, keep a maximum of n backups per project and if the total size of the CrashRecovery folder exceeds x GB, gradually reduce the number of backups to a minimum of 2 backups per project (where n and x are adjustable in the preferences).
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In my particular case, it seems like Fusion 360 started an auto save at 20:05:41 while Windows was collecting error info since 20:03:02 and just about to reboot:
With a project size of 190 MB there is certainly a long enough writing duration for this to seem plausible.
It might also be possible, that the timestamps are inaccurate and the auto save itself caused the blue screen, however, I find this less likely.
Either way, the current auto save system needs fixing asap!
