Windows won't update

Question

For the past two days I've been trying to update windows security update and I've tried almost every that the internet has told me to do and nothing has worked. I've done command prompts, deleting software distribution download folder, and date and time fix. The install error is 0x800f0991. I'm new to pcs so spare me a little.

Answer 1

Greetings!

I'm Christine, I'll be happy to assist you. Sorry to hear that you're getting error when installing Windows updates. This error usually means that the file needed is damaged or corrupted. No worries, I'll do my best to help you.

Have you tried to run the Troubleshooter already?

Please follow the steps below:

1. Windows Update Troubleshooter

Windows 11

Please Click Start menu and type Troubleshoot

Hit Other troubleshooters

And select Windows Update

Finally, Run the troubleshooter

Please check if the issue persists

2. Please click Start menu and type CMD, right click on it and choose Run as Admin, please paste the command below and hit enter.

DISM.exe /Online /Cleanup-image /Scanhealth

DISM.exe /Online /Cleanup-image /Restorehealth

Please wait for it to finish and repair the system files.

Once done, please paste the command below and hit enter.

sfc /scannow

Please wait to finish.

Check if the issue persists.

3. Reset Windows update services:

Please click start menu and type cmd, right click on it and choose run with admin

Kindly copy and paste the command lines below and hit enter:

net stop wuauserv

net stop cryptSvc

net stop bits

net stop msiserver

Ren C:\Windows\SoftwareDistribution SoftwareDistribution.old

Ren C:\Windows\System32\catroot2 Catroot2.old

net start wuauserv

net start cryptSvc

net start bits

net start msiserver

Please check if the issue persists.

4. Please try to perform an in place upgrade. In place upgrade will install the new features or updates of Windows it will also fix corrupted system files. Kindly check the steps below:

Video on how to perform in place upgrade:

https://www.youtube.com/watch?v=CAOwN68AInE&feature=youtu.be

Please go to https://www.microsoft.com/en-us/software-download/windows11

Look for Download Windows 11 Disk Image and select Windows 11 (multi-edition ISO)

• Once you're able to download the ISO, please right click and open it
• Please look setup.exe and run it
• Select yes if you will will be asked for User Control
• Choose Next to Continue
• Please read the License Agreement and once done, hit Accept
• Please wait until the setup program is done and it will check if your device space is enough for the update
• You will see the Ready to install page, please ensure that the Keep personal files and apps has been checked.
• Lastly, click INSTALL and follow the prompt.
• It will restart your device several times, please wait for it to finish.

This may take sometime depends on your connection or the performance of your device.

Please let me know the result. I'll be happy to assist you all the way until it's resolved.

Thank you,

Christine L

Independent Advisor

Standard Disclaimer: Youtube.com link is a non-Microsoft website. The pages appear to be providing accurate, safe information. Watch out for ads on the sites that may advertise products frequently classified as PUP (Potentially Unwanted Products). Thoroughly research any product advertised on the sites before you decide to download and install it.

Answer 2

The error code 0x800f0991 typically indicates that there is a problem with the Windows Update components or that some required files are missing. Here are some steps you can take to resolve this issue:

1. Run the Windows Update Troubleshooter: This built-in tool can help identify and fix issues with Windows Update.
   • Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters > Windows Update and run the troubleshooter.
2. Check for Required Updates: Sometimes, certain updates need to be installed before others. Make sure all prerequisite updates are installed. You can check for required updates by running the following command in PowerShell:

      Get-HotFix
   

3. Repair Windows Component Store: You can use the DISM tool to repair the component store. Open an elevated command prompt and run the following commands:

      DISM.exe /Online /Cleanup-Image /Restorehealth
      Sfc.exe /Scannow
   

   After running these commands, restart your computer.
4. Reset Windows Update Components: If the above steps do not work, you might need to reset the Windows Update components. You can do this by renaming the SoftwareDistribution and Catroot2 folders:

      Ren %systemroot%\SoftwareDistribution\DataStore DataStore.bak
      Ren %systemroot%\SoftwareDistribution\Download Download.bak
      Ren %systemroot%\system32\catroot2 catroot2.bak
   

5. Check for Disk Errors: Run a disk check to ensure there are no underlying issues with your hard drive. Use the command:

      chkdsk /f
   

   You may need to restart your computer to allow the disk check to complete.

If these steps do not resolve the issue, consider checking the Microsoft support site for further assistance or specific error details related to 0x800f0991.

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References:

• Windows Update common errors and mitigation
• Windows Update troubleshooting guidance