“Error occurred during a cryptographic operation” when decrypting Forms cookie
For anyone who hasn’t solved their problem, I was missing the “machineKey” entry for encrypt/decrypt in my web.config
cryptographicexception
CryptographicException was unhandled: System cannot find the specified file
Did you set the following on the application pool in IIS? Go to IIS Manager Go to the application pool instance Click advanced settings Under Process model, set Load User Profile to true See this stack question for further reading: What exactly happens when I set LoadUserProfile of IIS pool?