It amazes me sometimes how hard it can be to find a solution to a very common problem…

The scenario:

You are using Visual Studio 2008 or Visual Studio 2010 on Windows Vista, Windows 7, Server 2008 or Server 2008 R2, and are attempting to perform remote debugging to Windows XP or Server 2003. You are using domain credentials. Most likely you will receive an error in Visual studio that “A security package specific error occurred”. You may not be able to find anything in any event logs. The Windows XP remote debugging client says you connected ok, but it doesn’t work.

The long standing workaround is to create local users on both machines with identical names and passwords; then jump through a bunch of hoops to get things to run using the alternate credentials. This is FAR from ideal.

Turns out, it is a kerberos bug, and there is a hotfix. Install this on the Windows XP machine, and you will be remote debugging in no time!

http://support.microsoft.com/kb/969442
KB969442 – Error message when you try to connect to the Product Studio middle-tier server that is running on a Windows Server 2008-based computer from a computer that is running Windows XP: “Could not connect to the Product Studio datastore listed above”

It is unfortunate that Microsoft neglected to mention in the KB article that this also applies to Visual Studio.