When starting or configuring the Enterprise Single Sign-On Service (ENTSSO), you may get one of the following error messages:

Windows could not start the Enterprise Single Sign-On Service service on Local Computer.
Error 0x80131700: 0x80131700

ERROR: Could not contact the SSO server 'localhost'. Check that SSO is configured and that the SSO service is running on that server.
(RPC: 0x800706D9: There are no more endpoints available from the endpoint mapper.)

Could not create SSOSQL. To fix the problem, reinstall SSO or try 'regasm SSOSQL.dll' from a Visual Studio command prompt.
Error Code: 0x80131700

Failed to connect to the SQL database 'SSODB' on SQL Server 'SQLServerName'
0x80131700 (Win32)

Note ENTSSO is a required service for BizTalk and HIS. As a result, these services also fail to start.


This issue occurs after installing .NET Framework 4.0. The registration of the assembly used by ENTSSO to access SQL Server (SSOSQL.dll) does not specify the correct version of the .NET Framework.  When .NET Framework 4.0 is installed, the assembly will try to use the newer framework and then fail to load. 


To resolve this issue, install the fix available at the link below on the ENTSSO server:

Update for Microsoft Enterprise Single Sign-On v4 (KB2252691)

The hotfix will update the ENTSSO assembly registration with the correct version of the .NET framework.


You must have Enterprise Single Sign-On Service 4.0 to apply this fix.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

More Information

This issue can also be repaired by using the regasm tool to re-register the SSOSQL assembly. Regasm.exe is included with the .Net Framework.

32-bit Server

1.       Open a command window
2.       Go to C:\Windows\Microsoft.NET\Framework\v2.0.50727
3.       Type: regasm “C:\Program Files\Common Files\Enterprise Single Sign-On\ssosql.dll”

64-bit Server

1.       Open a command window
2.       Go to C:\Windows\Microsoft.NET\Framework64\v2.0.50727
3.       Type each of the following and hit ENTER:

32bit:  regasm “C:\Program Files\Common Files\Enterprise Single Sign-On\win32\ssosql.dll”
64bit:  regasm “C:\Program Files\Common Files\Enterprise Single Sign-On\ssosql.dll”

Note On a 64-bit server, regasm will need to be run for both the 32-bit and 64-bit versions of ssosql.dll.

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