Windows 11 Insider Preview Feature Update (26220.8754) Install error - 0xc1900101

I was getting the same error, for multiple attempts, but I was able to resolve it, and I suspect at least some of you may have the same culprit.

Not too long ago there was an article about applying a set of registry tweaks to use the "faster" "server" grade NVME Driver instead of the standard one.  Well, with this enabled you get this 0xc1900101, and it's not super obvious.

After the setuperr.log and setupact.log did not contain any useful driver failure messages, CoPilot helped determine the failure was happening pretty early on in the boot process which triggered the rollback.

Removing the registry tweaks posted here: https://www.ghacks.net/2025/12/26/this-registry-hack-unlocks-a-faster-nvme-driver-in-windows-11/

Then restart  and apply the update for 26220.8754.  For me it worked.

I have tried 5 times in 4 days, same error. Anyone here got it sorted?

I have tried at least 5 times but still the same, saw some tutorials as well on youtube but no success. Has anyone able to fix it.

Hi, 0xC1900101 is usually driver-related during a Windows feature update, even when Device Manager looks clean.

I would try this order:

1. Unplug nonessential USB devices and docks.

2. Update BIOS/UEFI, chipset, storage, graphics, Wi-Fi, and Bluetooth drivers from the PC maker's site.

3. Temporarily remove third-party antivirus, VPN, disk encryption tools, or tuning utilities.

4. Make sure there is plenty of free disk space.

5. Check C:\$WINDOWS.~BT\Sources\Panther\setuperr.log and setupact.log after the failed attempt.

If the same build fails repeatedly, Feedback Hub plus those setup logs will be the most useful next step.

I've been also been having the  exact same issue 

50 % of my company devices facing Slowness this week, please advise 

I have the same issue

Me too. 

I have the same issue same message.  Started in June.  Always fails on reboot.