Until recently, I was getting the message “Failed to load extension → Compospray” and couldn’t open files created using Compospray.
It’s a model with a lot of trees drawn on the slope of a mountain.
When I contacted Japan support,
I was told to "delete “CompoSpray” and “compoSprayToolbar.rb”, so I deleted them.
The error message no longer appears, but the file still won’t open.
This is the situation.
So “Compospray” can still be used in 2025. I deleted it.
You didn’t answer my question - are you working directly in a file saved on an external hard drive/network?
I used Google Lens to translate that text in the picture and from what you described, the error is not related to that extension (Compo Spray), but most likely the SKP file is corrupted.
If you search the forum (“Failed to open document” or “This does not appear to be a SketchUp Model”), you will find a lot of threads with this problem, from people that work directly on a file saved to an external hard drive.