I have a very strange issue that I cannot seem to determine the root cause.
SBS 2011 Server with all updates and fully patched.
All clients are laptops with windows 7 pro and have DHCP addresses from the SBS server and DNS pointing to the SBS server.
The network is wired and wireless with WPA encryption.
Randomly the clients cannot logon. When they enter their credentials they get stuck at the spinning circle with "Welcome" on the screen.
I have looked in the event log and do not show any errors such as group policy that they are getting hung at.
So far I have found three work-arounds.
1. Disable wireless adapter
2. Remove and re-add workstation to domain for temporary fix
3. Delete one of the DNS records in the SBS server for that workstation. There are two records because each workstation has a wireless adapter and Ethernet adapter with different ip's.