Fixed: Trust Relationship Between Workstation and Domain Failed
Every domain-joined Windows machine shares a machine-account password with the domain controller; the password rotates every 30 days, and when the local and DC copies drift apart the secure channel collapses and logon dies with: The trust relationship between this workstation and the primary domain failed. Four working fixes, ordered heaviest to lightest. Solution 1 - drop the machine to a workgroup and rejoin the domain (always works, two reboots). Solution 2 - Reset-ComputerMachinePassword -Credential from PowerShell (one command, no reboot, the cleanest fix). Solution 3 - cache a domain credential in Credential Manager (a workaround, not a fix - the underlying drift is still there). Solution 4 - right-click the computer object in dsa.msc and pick Reset Account, then reboot the client (the right answer when the desktop is unreachable). Includes the four root causes (long offline gap, snapshot restore, cloning without sysprep, replication lag) and which solution best matches each.