Visual Studio - "COM object that has been separated from its underlying RCW cannot be used" exception

problem:
In Visual Studio 2005
attempting to modify project settings for debug command line details,
show this error message:

"COM object that has been separated from its underlying RCW cannot be used" 

Soltion:

1. close the solution (you may need to kill the devenv.exe process)

2. delete the .suo local user options file.

3. open the solution again

You should now be able to edit the project settings OK.