Upgrade attempts to tonight’s new Insider Build 19546 failed twice when using Windows Update. Next, I tried upgrade using an ISO image made with UUP Dump. It failed, too.
I am already used to working through various issues with Insider upgrades, and have some routine preparations I’ll make every time before starting. These include: disconnect all external devices except mouse and keyboard, disable Windows Defender, and so on. Usually this helps, and in all honesty, I have had not too many upgrades fail lately.
But, tonight, I needed my secret weapon: upgrade inside OOBE, signed into the Windows system account Defaultuser0 (read all about that account in this earlier Win10.guru story). Here’s how to put this technique to work, in case you should need it in the future.
First, I copied the 19546 ISO from my downloads folder to Public\Downloads, because I would later in the process temporarily lose access to my user profile. Next, I created a new local admin account, and named it Dummy1. Then, I signed out from my normal user account, and signed into the Dummy1 account.
Next, it was time to disable all active user accounts, except the new Dummy1 account. The following command, run in an elevated Command Prompt does the trick:
net user USERNAME /active:no
This process involves Sysprep, which occasionally (but not always) breaks Start, Cortana and Windows Search on active user accounts. Thus, disabling them temporarily is a good insurance policy.
OK, that’s it for the preparations. One more check to see that all external devices are disconnected.
I press WIN + R to run the Sysprep command:
%windir%\System32\Sysprep\Sysprep.exe /oobe /reboot
Windows restarts and runs OOBE. When it stops at the region selection screen, Windows is fully functional and the user is temporarily signed in as Defaultuser0. Pressing SHIFT + F10 opens a Command Prompt window, and activates WIN-key shortcuts. Pressing WIN + E, I open File Explorer, I browse to the Public\Downloads folder and mount the 19546 ISO (double click or right click and select Mount)
That’s it. I can now run the upgrade from the mounted ISO:
After the upgrade, OOBE runs again. You must select region and keyboard, and so on. You also must create an initial user account. You cannot use any names already reserved by your temporarily disabled accounts, and you cannot use the name Dummy1 because it’s also reserved at the moment. I always use the Dummy2 username at this point, creating a local account without a password.
When Windows finally reaches Dummy2‘s desktop, it’s time to activate those temporarily disabled user accounts:
net user USERNAME /active:yes
When that’s done, sign out from Dummy2, sign in with your original admin account, and delete both of the Dummy1 and Dummy2 accounts. Notice that OOBE has changed the computer name: thus, you must change it back to the original one. Other than that, Windows is intact, exactly as it was before.
This may look complicated but it’s really quite simple. This method has not failed me yet, either. Instead, it has helped me to upgrade a few times when everything else has failed. I hope you do not need to use this technique, and that your upgrades go and work well. But if you do need it, please leave a comment and tell how things went. For me, it worked once again.
Author: Kari Finn
A former Windows Insider MVP, Kari started in computing in the mid 80’s writing code for VAX / VMS systems. Since then, he’s worked in a variety of IT positions. He specializes in Windows image capture, customization, repair and deployment as well as Hyper-V virtualization. Kari is a proud Team Member at number #1 Windows site TenForums.com.