The SQL setup won’t start when you double click setup.exe, when executing setup.exe from command prompt you will receive the following error:

ERROR: Runtime error: This method explicitly uses CAS policy, which has been obsoleted by the .NET Framework. In order to enable CAS policy for compatibility reasons, please use the NetFx40_LegacySecurityPolicy configuration switch. Please see for more information.

Error message


The solution is to remove .Net Framework 4.5

After removing you can install SQL.



Posted in: Microsoft, SQL, Windows 2008 R2, Windows 2012