Newest version of GDevelop won't open my past project file

I opened GDevelop and my project worked just fine, GDevelop said an update was available, so I closed and restarted GDevelop and now I get the

" The project file appears to be malformed, but an autosave file exists (backup made automatically by GDevelop). Would you like to try to load it instead?"

auto save file does not work either.

It’s a valid JSON file, no parsing errors. Any ideas? This happened once before, I was able to open on an intermediate GD version on a separate computer, save that, then try on the new GD version. I’ve been backing everything up on GitHub so I have all of the details of any changes. But zero changes occurred to the file between the last version of GD and this one.

here is the JSON

I noticed this is a multiple files project. Are all the sub-files intact?

Hi Gruk, thanks for your help. Yes all sub-files are intact/unmodified since the previous GDevelop version that did not have any issues opening the project.

It is very mystifying. I opened GD just fine with my full project, GD alerted me a of a new version, I closed and reopened GD and this error started occurring.

I still have GD open on a separate computer with the last version of GD and the same files work fine (pulled down from the GitHub repository I have).

well good news, I re-downloaded and reinstalled GDevelop and now the project is working. No idea what was wrong, but at least I didn’t lose all my work!