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Windows Update Error 0xC1900101- 0x40021

I've been trying to update my laptop for the past few months and I've only been getting the BSOD and this error.

I'm on the Windows 11 21H2. I've been using the Windows Updates, and even the Windows Installation assistant, I just can't seem to get past this.

Attaching the Panther and Rollback, since I usually see this being asked.

Thank you so much in advance.

Answer
Answer

Please do a clean boot. A clean boot is the process of starting Windows without loading third-party apps and services. Please see this Microsoft article for more information.

 

How to perform a clean boot in Windows - Microsoft Support:

https://support.microsoft.com/en-us/topic/how-to-perform-a-clean-boot-in-windows-da2f9573-6eec-00ad-2f8a-a97a1807f3dd

 

(Step 3 is very important. You need to first enable "Hide all Microsoft Services" before clicking "Disable all".)

Once done, reboot Windows and try the ISO method posted by Dave.

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Ramesh, Windows Shell MVP 2003-2012.
If this post resolves your issue, pls mark it as an Answer.

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Answer
Answer
Hi, I am Dave, I will help you with this.

Your version of Windows 11 is 3 years out of date, you are missing versions 22H2, 23H2 and the new24H2 feature updates.

The most successful method to install version 24H2 is to use the Windows 11 ISO.

Please follow the steps, this is then not like re-installing Windows, it is just like an update and your personal files, settings and installed software will not be affected.

Click this link:
https://www.microsoft.com/software-download/win...
to download the Windows 11 ISO

When the ISO file completes downloading

Disconnect from the Internet

Disconnect all external devices with the exception of a mouse or keyboard.

Temporarily disable any 3rd party Anti-virus you may have installed

Then, in Windows File Explorer, double click the ISO and then run Setup.exe and select the Install option.
___________________________________________________________________

Power to the Developer!

MSI GV72 - 17.3", i7-8750H (Hex Core), 32GB DDR4, 4GB GeForce GTX 1050 Ti, 256GB NVMe M2, 2TB HDD

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Question Info

Last updated April 16, 2025 Views 143 Applies to: