Staring at a blank desktop, due to event 4006

The event is [The Windows log on process has failed to spawn a user application. Application name], when we use win2012 64bit, event the non administrator user
already in the administrator group, winlogon still failed to start the userinit registry value AP. Root cause is UAC will restrict the non system AP started by winlogon,

after close UAC function, it would be ok.