I received error message "Unable to start debugging on the web server" in Visual Studio 2010. I clicked the Help button and followed the related suggestions without success.
This happens with a newly created local ASP.Net project when modified to use IIS instead of Cassini (which works for debugging). It immediately pops up the error. Nothing shows up in the Event Viewer. This also happens with VS2008. Debugging used to work.
I am able to attach to the w3wp process to debug. It works but is not as convenient as F5.
I posted the problem at Experts-Exchange and StackOverflow. The answer came from Jeroen at StackOverflow:
- In Regedit, navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa
- Right-click Lsa and create a new DWORD value
- Name it DisableLoopbackCheck
- Set its value to 1
- Reboot (instead, I killed the msvsmon.exe process and restarted Visual Studio)
My website (and IIS7.5) is on my local PC (Windows Server 2008 R2).
After finding that solution, I searched a bit on LSA and found this related KB article: http://support.microsoft.com/kb/896861 – it’s about IIS 5.1! It is something about a loopback security check that helps prevent reflection attacks.
Also reference Min Kwan Park’s blog which has lots of possible solutions for various debugger issues (though this is and old posting): http://blogs.msdn.com/b/mkpark/archive/2004/03/09/86872.aspx
[Update]
The debug started to fail again in the same way, immediately displaying the Unable to start debugging error after the compile. Killing the msvsmon and restarting VS2010 did not help. As soon as I click F5, msvsmon.exe shows up on the taskmanager list and the error displays.