Could not load type 'System.Runtime.CompilerServices.ExtensionAttribute' from assembly 'mscorlib

Question

When starting up my web site for the first time, I\'m getting this error

Could not load type \'System.Runtime.CompilerServices.ExtensionAttribute\' from assemb

Answer 1

I did encounter the same problem while trying to read data from a Firebird Database. After many hours of searching, I found out that the problem was caused by an error I made in the query. Fixing it made it work perfectly. It had nothing to do with the version of the Framework