Network managed by Windows Server 2008 R2 with all clients Windows 7 Pro 32 bit. I have a couple of clients that generate a message that the trust relationship has been lost with the domain controller. I have one DC and about 150 clients. I wanted to log on locally as the local administrator but when I tried to do that I got a message that the group policy service had not started. I tried safe mode but could not log on. So I have a couple for questions - 1) How do I solve this problem and get this computer to rejoin the "trust relationship" and 2) what causes this and how can I prevent it?