"Sources directory is already netbeans project" error when opening a project from existing sources

Thank you!

I was having the same problem:
Sources directory is already NetBeans project (maybe only in memory).

Netbeans creates a folder in your project named "nbproject". Once you delete that, restart the IDE and you're good to go.

When you create a NetBeans project from existing sources, NetBeans uses the same directory to add its own files: a netbeans folder with .proj files.

Solution: delete the netbeans folder and restart the IDE. Opening a new project should now work.

1. Go to the folder containing your project
2. Delete the folder named nbproject
3. Restart Netbeans
4. Try creating your project again from the original folder