Screenshot by Ed Bott/

For the past few months I've been running the latest Insider preview releases of Windows 11 on my main PC. In preparation for the version 22H2 feature update, which was released in October, I moved to the Release Preview channel. Because those versions have already been through testing by larger groups in the Dev and Beta channels, that's a fairly low-risk strategy. But it's not without occasional hiccups.

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Recently, I ran into one of those annoying low-grade bugs that are inevitable when you live on the leading edge. Windows Update told me a cumulative update was available for my PC. 

But every time I tried to install it, the update failed with a cryptic error code: 0x800f0990.

I tried every troubleshooting trick I know and couldn't get that update to install.

Did I care? Not really. 

Also: How to factory-reset your Windows 10 PC

Because I knew I could fall back on the ultimate Windows troubleshooting trick, a time-tested technique that swats away those pesky error codes like a big ol' digital flyswatter.

If you find yourself in a similar situation, feel free to break out the same big gun I did: The Windows repair installation, effectively an in-place upgrade using the same version that's already installed. It works for Windows 10 and Windows 11.

This solution is considerably less drastic than a Windows reset, which wipes out your current installation and forces you to reinstall apps and restore settings. A repair installation "upgrades" your Windows PC using the same major version that's already installed. In the process, it restores settings to their normal state, undoing whatever tiny change is causing your current issue.

The ultimate Windows troubleshooting trick

1. Download the installer files as an ISO

An ISO file is a single compressed file that contains the digital equivalent of a Windows installation DVD. You'll find downloadable ISO files that correspond to the Windows version you're currently running in these locations:

• Windows 11 General Availability (GA): If you're running the current public release of Windows 11 (what Microsoft calls the General Availability channel), you'll find it here: https://www.microsoft.com/en-us/software-download/windows11
• Windows 10: The overwhelming majority of Windows PCs in the installed base today still run this tried-and-true OS. Get it here: https://www.microsoft.com/en-us/software-download/windows10
• Windows 11 Insider Preview: If you're living on the bleeding edge, Microsoft has your ISO here: https://www.microsoft.com/en-us/software-download/windowsinsiderpreviewiso

Also: Microsoft starts rolling out annual Windows 10 feature update, Windows 10 22H2

2. Mount the ISO as a virtual DVD drive

Double-click the ISO file to mount it in Windows as a virtual drive. In File Explorer, it's indistinguishable from a DVD drive, with its own drive letter.

3. Run Setup from the virtual DVD drive

Double-click Setup and wait while the Windows installer goes out and gets the latest updates. Well, not exactly the latest. As part of the fail-safe protocol, the installer downloads the next-to-last cumulative update. That precaution keeps you from getting tripped up if the most recent cumulative update is the cause of your current crashes.

Choose the option to keep all your personal files, apps, and settings, and then click Next.

Screenshot by Ed Bott

Also: Yes, you can still get a free Windows 10 upgrade. Here's how

4. Return to normal

After installation is complete, restart and then check Windows Update to get the most recent cumulative update.

After I finished these steps (it took roughly 20 minutes), the update that had been giving me fits installed without any issues. As a bonus, another problem that had been annoying me for a few weeks was also solved. Previously, each time I restarted my PC, the infrared camera that handled Windows Hello face recognition had been unavailable, which meant I had to key in my PIN to sign in for the first time. After completing the in-place reinstall, that face recognition worked again.

Although it seems like a drastic step, doing an in-place repair install is a surprisingly low-key solution that has a way of solving even particularly annoying problems. If you're stumped, give it a try.

See also

How to screen-record in Windows 10 or Windows 11How to improve your Windows laptop's battery lifeHow to replace your Windows 11 Start menu with a third-party appHow to use the free PowerToys FancyZones in Windows and why you shouldHow to manage your security questions for a local Windows account

• How to screen-record in Windows 10 or Windows 11
• How to improve your Windows laptop's battery life
• How to replace your Windows 11 Start menu with a third-party app
• How to use the free PowerToys FancyZones in Windows and why you should
• How to manage your security questions for a local Windows account