Windows could not start the Enterprise Single Sign-On Service
I am getting a few reports that after a recent windows update (or installing .NET Framework 4.0) the ESSO service fails to restart. Microsoft have released a hotfix to address this (http://support.microsoft.com/kb/2252691)
Microsoft Reports:
This issue occurs after installing .NET Framework 4.0. The registration of the assembly used by ENTSSO to access SQL Server 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 manually:
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.
Hope this helps 
