SQLCLR using the wrong version of the .NET Framework

Question

During a recent restart of our development server the SQL Server started using .NET 4.0 for the SQLCLR. This means that nothing using the CLR in SQ

Answer 1

I experienced the same annoying problem. None of the Geography/Geometry stuff in my database worked. Took me some unsuccesfull reinstalls of SQL server to finally (some weeks later!) find the following key in my registry had been set to '1'

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework\OnlyUseLatestCLR

when I reset it to '0', and rebooted the machine, things worked again!

Hans