<p>On my <strong>Windows XP</strong> machine Visual Studio 2003 2005 and 2008 all complain that I cannot start debugging my <strong>web application</strong> because I must either be a member of the Debug Users group or of the Administrators group. So, I am an Administrator and I added Debug Users just in case, and it still complains.</p>

<p>Short of reformatting my machine and starting over, has anyone encountered this and fixed it [with some undocumented command]?</p>

You could try running "
```
VsJITDebugger.exe -p <PID>
```
" on the command line. I've had a simalar situation and been able to debug the application using the above.
"
```
VsJITDebugger.exe /?
```
" will show you all the options.
The PID can be found either in the task manager (view->Select Columns...) or Visual Studio's Attach to Process.