The server has encountered a critical error. The Shared Services Database; has returned a session state entry with an unrecognized ...

The server has encountered a critical error. The Shared Services Database; has returned a session state entry with an unrecognized version. If you're in the process of patching the server, please ensure that all Web front ends have been upgraded before restarting them. If this error continues to occur, check your database settings and hardware. (User: %1, IP: %2, Request: %3)