Help!! I am using the Mindstorms app on a HP laptop to program missions to an EV3 brick for a robotics team. We saved our programs yesterday after finishing programming a couple missions. Today, the file will only open in Mindstorms to the lobby with no programs opening at all! The file itself says I last saved to it yesterday, and it says there is 40 KB in there, but it won’t open. I have tried restarting computer and Mindstorms app, sending the file to another computer with that app (won’t open) and searching for it saved somewhere else on the laptop…all a no go! I have also opened last years file and it opened just fine, so I don’t think it is the Mindstorms app. Can anyone help with suggestions on how to get my file opened and get the programs back? We have 2 1/2 months of programming on there and we have qualifiers in 3 weeks!

  • 4
    I’m voting to close this question because this question is not about LEGO but rather about recovering files in Microsoft Windows.
    – Phil B.
    Dec 22, 2021 at 13:01
  • 4
    Do you have a backup copy of the file available (possibly an older version) ? Can you open the ev3 file as a zip file (and if so what's in it) ? Did you transfer the program to the ev3 brick ? Dec 22, 2021 at 13:04
  • I agree with Phil: this question has little to do with the site's scope. Still, I feel sorry for you for losing all your hard work - this must be truly terrifying to you all. What you still can do: 0) Create a backup of everything that is left NOW. 1) Try to find older versions to restore. 2) Try to rename a copy of the file to .zip and open it, comparing it to a working file. 3) Get in touch with the Mindstorms app developers / maintainers - they might have a tip about possible backup file locations or recovery steps.
    – zovits
    Dec 23, 2021 at 9:41

1 Answer 1


I don’t think this question is about LEGO, but rather about Microsoft Windows (assuming that is what runs on the laptop) and hence it doesn’t fit here on this forum. However, here are some suggestions:

  1. It looks like your file has been corrupted during the previous save. To prevent this in the future, it is best to make a copy of the program at the end of each day and keep it somewhere safe, for example on a USB thumb drive. This will also save you if your computer were to crash some day.
  2. In the meanwhile, try going to the File Explorer in Windows, find the saved file and right-click on it. Hopefully it shows something like “show versions” which might allow you to find the state of the file from a previous save.
  3. If that option is not there (and it very well might not be), use this as an opportunity to teach your grouo about the value of backups, and redo the programs. If this is for FLL, you might have printouts of the programs for your binder, which you can use to recreate the program?

Good luck.

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