Can't install cumulative updates

Hello! I would like to know what are the ways to update Windows to the latest build without using Windows Update? I have been unable to install the "Cumulative Updates" for a few months due to error 0x800f0991. I have tried running the image repair commands through CMD but it did not resolve. I have also tried installing the updates through the standalone installer downloaded from the Microsoft Update Catalog.
Any help is appreciated!

Hello @KeSun and welcome to ElevenForum.


Might be time to try a Repair Install via an In-Place Upgrade. Try Option #2, here...

Welcome to elevenforum. Turn off any 3rd party antivirus, including Malwarebytes during troubleshooting. Make sure no AV processes are left running in task manager.

One of the following steps should fix the problem. I usually do 1-4 in any case.

1. run troubleshooter-settings-system-troubleshoot-other troubleshooters-windows update-RUN.

2. Reset Windows update using Brink's tutorial Reset Windows Update in Windows 11 Tutorial

3. CLEAN UP COMPONENT STORE - dism /online /cleanup-image /startcomponentcleanup
Analyze and Clean Up Component Store (WinSxS folder) in Windows 11 Tutorial
4. Run sfc (even if you've done it already) but do it again after resetting update components.
Open a command prompt as administrator and type sfc /scannow
Pay attention to the scan results to see if SFC found anything it could not repair. If it found corruption it could not fix followup with this command (note the spaces)
dism /online /cleanup-image /restorehealth
Restart computer

(Note-you can follow up with another sfc /scannow command to make sure that dism repaired the files)

Restart computer and Try Windows update again. If it still fails do step 5.

5. Do a repair install. Repair Install Windows 11 with an In-place Upgrade Tutorial

You can find all the updates at Microsoft Update Catalog:
or at UUP dump site:

To see the KBxxxxx code to search, look at the News section of this forum.