While Piskel isn’t actually part of the GDevelop engine just bundled with it, there are a few common things that will cause you issues for both Piskel AND your project.
You’re experiencing one of them right now: You cannot utilize OneDrive folders, or folders synced with OneDrive, as a project location. It will restrict Piskel from being able to create files (like you’re experiencing), as well as lead to potential corruption of your project files themselves.
You’ll need to move your project to another location that isn’t stored within your OneDrive.
For me it’s because you use OneDrive, I can see it in the path on your screenshot.
OneDrive isn’t a classic folder, but a synced folder that causes trouble to softwares.
It’s not letting me move it!
You have tp move your entire project. Not i side of Gdevelop/piskel. On your computer. Woth GDevelop closed before you move it.
Now it’s not letting me open it!
Make sure you are browsing to the project file in the open dialog, not using the recent projects list.
Otherwise this is likely the onedrive related corruption I mentioned above. Can’t really provide any other help beyond that.