We started getting Error: Unable to find the requested .Net Framework Data Provider. It may not be installed. But framework is loaded and this just started happening. We can logon but not navigate anywhere.
.Net might not be working or be corrupt. Navigate to the \Windows\Microsoft.net\Framework\vXXXX\Config\
Folder and open the machine.config (this should only be done my IT on the server)
Please see screenshot on what to remove from the machine.config. (extra entry) save and try it again.