It is a security issue, i had Everyone but had to add Domain Users as well

C:\Documents and Settings\All Users\Application Data\Microsoft\Crypto\RSA\MachineKeys

or

C:\ProgramData\Microsoft\Crypto\RSA\MachineKeys

Give appropiate permissions.

If Windows 8 or older, FMLOGIN.INI must be copied to C:\Users\user\appdata\local\virtual store\program files\materials control