I installed a couple of servers recently on 2016 using the Evaluation as we hadn’t received the correct keys. Now, usually, I’ve found that using this method of setting the correct key, or simply changing the product-key from the properties of ‘My Computer’ worked, however for these units I kept getting this error:
This Edition Cannot Be Upgraded
This did not bode well as we’d done a fair bit of work on the deployed servers. Yes, yes I know….
Anyhow, I did some investigation with the DSIM tool, and it turns out you can actually use that tool to upgrade the license, and it worked just fine.
Firstly, check to see what versions you can upgrade the license to, or rather check to make sure the version you want is in the list. You can do that with:
Dism /Online /Get-TargetEditions
You should get an output similar to this:

We can use the same tool to set the license key and upgrade it the full version. That command is:
-> Dism /Online /Set-Edition:ServerStandard /AcceptEula /ProductKey:<key>
It take about 20 minutes per server to run (so be patient) but it worked out just fine. Anyway, I hope somebody out there finds this useful.
