When logging into Windows, occasionally the following error will pop up :
"The trust relationship between this workstation and primary domain failed."
This is caused when the server and computer no longer can securely identify each other. There is however a very simple fix to this. First you must log in locally to the machine
Then you must rejoined the machine to the domain.
This is the same process as joining a machine to the domain, however you must first switch it off the domain to a workgroup (workgroup name can be anything). Then you can join it back to the domain.