Tl;dr Is it possible to convert a Windows 10 Pro install back to Home without reinstall the system? ========================================== I work for a company who gives phone support to Windows users. Among the calls, we receive more than 100 calls/week with users who took their computers to 'technicians' who basically delete the original windows installs from their clients and reinstall a Pro version activated with KMS. This actually happens a lot here in Brazil for some reason. Well, most people here doesn't have a good internet connection, so download a Windows ISO and reinstall the system usually takes a long time. Right now what we are doing is basically download a Windows ISO directly from Microsoft, mount them, modify the CompositionEditionID and EditionID values on HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion to 'Core' and run the setup.exe from the ISO to do the trick and do an In-Place install from Pro to Home keeping all files and programs. As I said, most of our clients doesn't have good internet speeds, so I was thinking if there is a way to change from Pro to Home without the need of a 4gb download. Something like a simple changepk.exe /productkey <clientkey> or DISM /online /Set-Edition:Core /ProductKey:<clientkey> I know that are some packages that are exclusively from Core and CoreSingleLanguage versions that aren't present on greater Windows versions. 53 packages to be exact. All of them only take around 200mb. I've tried to extract all of them using the Aunty Mel's Cheap And Nasty SxS Package Extractor and apply them with DISM on a online Windows 10 Professional installation, but when I try to change the Windows version to Home it doesn't work. Analyzing DISM.log I saw an error when I try to run DISM /online /Set-Edition:Core /ProductKey:<clientkey> related to Microsoft-Windows-CoreEdition~31bf3856ad364e35~amd64~~10.0.18362.30.cab package. error 0x80070002. I have even tried to download the file microsoft-windows-editionpack-core-package.esd, convert to cab using @abbodi1406 ESD2CAB-CAB2ESD script and reapply the package, but it didn't succeed either. I can't get pass from this point. Isn't possible to do this after all? Am I missing something? If someone have any ideas, please share with me so I can try. It will greatly improve my work and from my coworkers too.