I happen to have more than a couple of dozens Windows Server VMs in my HomeDC, starting with Server 2003 and ending with (the gorgeous) Server 2016.
I tested 2016 along with various products (including XenDesktop, Horizon View, VEEAM) since I first got my hands on the Tech Preview 1 and as per today, I have close enough to 15 VMs running with the 2016 Evaluation version. I didn’t really wanted to reinstall EVERYTHING just because Windows doesn’t want to switch “automatically” from Evaluation to the new Product Version for which I had a license, so I started digging into DISM.
So, what’s to be done?
Open an elevated Command Prompt (Win+X, then A) and type:
DISM /Online /Set-Edition:ServerStandard /ProductKey:Your-VLK-Product-Key-For-WindowsStandard /AcceptEULA
NOTICE: If you have a Datacenter edition, you might need to set the edition to “ServerDatacenter” as it was the case for me.
At the end (yeah, it takes a while…), the process might request a reboot, so reboot your server and then check the Activation status.
PS: Not sure if this works for the Core edition. Didn’t had the time to test, but I guess it’s not working. 
Victor an End User Computing Consultant. You find him most of the time on Twitter (@01004753) but also on LinkedIn evangelizing new technologies and processes that can change in good, the world we live in. Victor has expertise in Server & Client Virtualization, Client Management, GPU Virtualization, HyperConvergence and Enterprise Security
Victor Homocea 
excellent blog and super helpful just a small mistake you did is there is spelling mistake of “ServerDatacenter” please change it.
Currently its “ServerDatancenter” so it gives error message at the end
Thanks!
Modified it 😁
How long does this take? Been an hour so far.
For me it took about 10-15minutes but my VMs were on SSD storage and idle host CPU.
It seems to take 1hr but I’d say you have nothing to lose if you wait 🙂
O processo ele da uma travado no meio do caminho em 10%, verifique na CPU do Task Manager quando ela cai pra menos de 5%, nesse momento volte no prompt de command e aperte ENTER, você vera que a CPU volta a fritar a ativação!
it working, thanks victor.
Worked great!! Thank you very much.
Worked perfectly; thank you!
worked well
Finally found a solution that worked. Thanks for the taking the time to share.
Hey, I got the below error:
Deployment Image Servicing and Management tool
Version: 10.0.14393.0
Image Version: 10.0.14393.2457
Error: 87
The specified product key could not be validated.
Check that the specified product key is valid and that it matches the target edition.
Any suggestions?
TIA
Prashant
Hey Prashant,
Seems there’s an issue with the product key you used. You’ll need to use a Product Key that matches / works with the product you want to switch to.
I do hope you’ve opened an elevated Command Prompt, since that can cause a lot of crazy errors that might have no sense.
Hey Victor,
Thanks for your reply. I did realize that I entered the key wrong after I posted the query above, it worked after I changed it. However the “removing package……..” process is stuck on 10.0% for more than 15-20 mins now.
Yeah, well… That’s not a fast process. Take a longer break or do anything else in the meantime.
Check the CPU usage in task manager
Thanks for your support…
Glad I could help Jha!
Thanks for your help, this worked for me
Glad I could help Jorge!
Victor,
I have come accross the deal where my vm’s shutdown now every hour, so when I run this commend sometimes it takes more than that and messes the whole process :(… any advise for this? Like to avoid shutdowns or so?
Thanks
Hey Bob, You’ll need to either to first activate the OS and then change the edition or move the VMs on to faster CPUs and SSD-based storage in order to ensure the edition is changed before the OS reboots itself due to the Activation issue.
Worked Perfectly well for the Hyper V server. VMs still on the process and is ongoing for last 10 hrs, RAM is 8GB for VMs, maybe will take more time.
Work great. *kisskiss