How should I fix this error: load failed: unknown solution item type

I’m using unity for the first time. So I saved my scene, then proceeded to make a new script. I made a game object, added the component and it was fine. I then opened the script inside monodevelop and it comes up with the error below.
Here’s the full error:
Thank you for the help!

Ok So I’ve got a few solutions.

1.) Check your external editor in preferences in unity, and make sure that they’re set to the external editor that you want. For me I wanted Monodevelop, but it was set to Visual Studio. I think this was most likely the problem. However, I uninstalled and reinstalled unity before doing this so I’m not sure.

2.) This leads me to option 2. Just uninstall and reinstall unity. This is more of a hassle so I recommend option 1 first.

Also it could be that you have multiple versions of unity installed, so check that.

I hope this helps anyone with similar problems!

i had the same errour i just changed Unity folder from programs folder to program files (x86) ,
and i did restart to unity and mono dev and it work