Recently, I encountered a situation that brought an entire office environment to a standstillāand it all started with a failed Windows Server Active Directory (AD) instance.
The Problem
The Windows Server AD crashed unexpectedly. Despite numerous attempts to bring it back online, it refused to boot. I had to revert to a previously taken VM snapshotāa seemingly simple fix that opened the door to a larger, more complex problem.
The moment the snapshot restoration completed and the AD server came back online, we began experiencing a strange issue: every workstation that was powered on after the AD server recovery couldnāt log in. Passwords were being rejected, and users were hit with ādomain trust relationship failedā errors.
Yet, curiously, machines that were turned on before the AD was restored worked flawlessly.
This anomaly created confusion and panicāstaff couldnāt work, and productivity was grinding to a halt.
Digging Into the Issue
At first, I tried resetting affected user passwords from the AD. The password changes were accepted, and users could seemingly log inābut then a new problem emerged. The moment a user logged in, the system would restart within 30 seconds. At first, I suspected background updates or scheduled tasks. But after a few cycles, the pattern became obvious: successful login ā restart ā loop.
I noticed something peculiar: this issue only occurred when the system was connected to the same network as the AD server. When I moved a system to a different (isolated) network and logged in, it worked perfectly and didnāt restart.
This opened a new line of investigation.
The Root Cause
Hereās what happened: When I reverted the AD to a previous snapshot, the secure channel passwords between the domain-joined machines and the domain controller were no longer in sync. Thatās what caused the trust relationship errors.
But the random restarts? That turned out to be the result of a corrupted trust state combined with a background policy or authentication failure that triggered system shutdowns after loginālikely due to security policies interpreting the session as compromised or invalid.
The Solution
Hereās how I resolved the issue:
1. Disconnected the affected workstation from the primary network.
2. Joined a separate (isolated) network.
3. Logged in using the user's AD credentials ā login succeeded without restarts.
4. Disconnected the PC from the domain.
5. Logged in using a local administrator account.
6. Reconnected the system to the same AD domain.
To my surpriseāand reliefāno user files were lost. The local profile folder under C:\Users{username} remained intact, so users picked up right where they left off.
This approach worked across multiple affected PCs, and I was able to fully restore functionality in about 2 hours.
Lessons Learned
Always be cautious with snapshot reversion in AD environments. AD databases are sensitive to time-based changes.
Network segmentation is a useful diagnostic tool.
Sometimes, the fastest path to resolution is to rebuild trust from scratch by rejoining systems to the domain.
Final Thoughts
What started as a system-wide outage turned into a satisfying problem-solving experience. While about two hours of productivity was lost, we also avoided a full-blown recovery crisis. It was a reminder that being calm, curious, and methodical in your troubleshooting can turn any situation into a win.
Top comments (2)
This is part of the reason why you should always have two domain controllers - if one has issues, just blow it away and make a new one! (a bit simplified, but..)
Blow it away is a strong word ššš