...Can't Login to DHCP Server With Domain Account After Dcpromo Demote

Hi,

 I demoted our DHCP server from being a DC and now I notice some odd behaviour. The server is a 2008 R2 DHCP server 

which was a non GC DC and held none of the FSMO roles. I ran a dcpromo to uninstall AD services from the DHCP server, 

ensured I did NOT tick "this is the last DC in the domain" and I choose "delete the DNS delegation pointing to this 

zone". All my DCs are 2008 servers running in a mixed mode domain. After demoting the DHCP server I'm noticing some 

odd behaviour:

1. Logins with domain administrator accounts fail to display the desktop (I simply get a blank screen). Task manager 

fails to run. Checking the event logs I see the odd memory leak warning, as well as "The windows logon has failed to 

spawn a user application. Application name: .Command line parameters : c:\windows\system32\userinnit.exe"

2. I can login as a local administrator and load applications OK, however if I right click on an application and go to 

run as then enter my domain admin credentials I receive access denied. My domain admin account is a local 

administrator on the server.

3. All services run OK.

4. DHCP status is OK and addresses are leased Out.

I'm a bit surprised that removing the AD role has caused this failure to login.

Thanks in advance