Failed to open project. Check it is a valid Construct 3 folder project.

Was working earlier. Now I can't open my project... I get the following error.

Console screenshot:

I was very upset, I don't know what to do. The closest backup (of the project file) is very old. What can be done to return the project.

Looks like some files in the project are missing or corrupted.

Check the files mentioned in the console error messages, for example gg_anim-faling-000.png

If this file exists, try opening/saving it with a program like Paint. Or try restoring it from older backups, or replace it with another file of similar resolution. See if it makes the error message in the console to go away. Do this for other files.

Thanks it helped. But I still don't know how the file could disappear. I did not upload this file to the project. I just copied the animation (сtrl+c ->ctrl+v) into the sprite and rearranged the slides.

Who knows, maybe there was some glitch with saving the project. Make sure to create backup copies, or configure automatic backup in C3 settings.