Enterprise SSO Won’t Start!

All my BizTalk Server hosts died on me the other day. When I attempted to restart them, I saw the following exception message:

Windows could not start the Enterprise Single Sign-On Service service on Local Computer.

Error 0x80131700: 0x80131700

Fortunately, the BizTalk console also provides easy access to event logs through the “Classic Event Viewer” (which I happen to like better than Windows Server’s newer event viewer, anyway). It gives a hint to the solution of the problem:

Could not create SSOSQL. To fix the problem, reinstall SSO or try 'regasm SSOSQL.dll' from a Visual Studio command prompt.

Error Code: 0x80131700

Re-installing SSO didn’t sound very appealing to me so I tried what the error suggested, which was to re-register the SSO SQL assembly. From the Visual Studio command prompt, you run the following:

C:\regasm "C:\Program Files\Common Files\Enterprise Single Sign-On\SSOSQL.dll"

Then I was able to restart SSO and BizTalk.

Interestingly enough, the cause of the issue was that I installed .NET 4.0 on my machine. The SSO SQL assembly tries to use .NET 4.0, when it still needs to run on an earlier version of the framework. A re-register sets it straight.

Microsoft has a knowledge base article about this problem and a patch which you can access here: http://support.microsoft.com/kb/2252691