When a Windows Server has 2 names after Windows Update.

It happens, you’re installing windows updates on a mission critical server, and the restart process gets stuck. Tens of minutes pass by, we get impatient, and we reboot by force.

This is the story of when forcefully rebooting causes a pretty weird problem. An exchange server got renamed, sort-of. At a lower level, the server was renamed as if it were syspreppred (indicated by running “systeminfo”), but in the properties of the server, or even typing “HostName” in CMD, displays the proper name:

Windows server displaying 2 different server names.

Windows server displaying 2 different server names.

What’s troubling is that all communications with Active Directory failed because the server is using a generic server name, not the one specified in the AD account. This causes exchange to fail.

Very Bizarre, but the biggest problem with this as you can see in the screenshot is that simply re-renaming the server doesn’t work. We need to dig deeper to change the computer name.

Can't Rename the computer through traditional means either..

Can't Rename the computer through traditional means either..

 

To fix this issue, we need to go into the registry and modify the computer name manually. Before doing this, just be sure you have a backup, modifying the registry can have some very negative effects. The keys to check are in the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ComputerName\ActiveComputerName and HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\ComputerName\ComputerName

Location of the Registry that contains the bad server name.

Location of the Registry that contains the bad server name.

The key is ComputerName, modify to the appropriate name, and reboot!

 

One thing that I really want to emphasize is to not remove and re-add to the domain. In my case that could have caused MAJOR issues with Exchange. The SID did not change, so it’s important to keep the SID intact to prevent further issues.