We will go through the steps required to convert a Windows Server 2016 Standard Evaluation to a Standard, the same process can be followed by Datacenter edition.
I had this issue last week in one of my labs, the Domain Controller was shutting down for any special reason, so when I logged on the console I realize that I was using the Evaluation for too long.
Before starting, let’s check using winver command the current version that we have.
To check if the server is registered or not, you can always go to Control Panel, System and Security and System. You can always try to activate it using Activate Windows option located on the right side.
We can try to activate using slui command which will bring this blue window where we should add the Serial Number of our Windows Server 2016, however when we are moving from an evaluation version, we may get the error message This edition cannot be upgraded.
If you are getting this error above, then a possible workaround is using dism to enter the serial number. The following command can be used:
dism /online /set-edition:ServerStandard /ProductKey:XXXX-XXX /AcceptEULA
A restart will be required, do so, and after that we can activate windows without any issues.