Fix error 0x0000066E when uninstalling Windows updates

This error means Windows won't let you remove a security or feature update. The fix is different depending on whether it's a normal update or a driver update.

When does this error show up?

You get error 0x0000066E — full text: ERROR_PATCH_REMOVAL_UNSUPPORTED — when you try to uninstall a Windows update through Settings > Windows Update > Update history > Uninstall updates. You click the Uninstall button, it churns for a bit, and then throws that error. This happens most often with cumulative security updates (like KB5034441 or similar) but also shows up for some driver updates pushed through Windows Update.

What's actually happening here is the update was designed as a permanent part of the system. Microsoft marks certain updates as "not removable" at the installer level. The error code 0x0000066E is the system's polite way of saying "I physically can't reverse this, so I'm not going to try."

Root cause

There are three reasons this error pops up:

The update is a security baseline fix. Microsoft sometimes ships updates that patch core system components — these are marked as permanent because reversing them would open a security hole. The update itself contains a flag in its manifest that tells WUSA (Windows Update Standalone Installer) not to allow removal.
The update is a driver or firmware update. Driver packages installed via Windows Update are often written directly into the driver store. The uninstaller isn't built to remove them cleanly, so Windows blocks the attempt.
The update's installation source is missing or corrupted. When you uninstall a Windows update, the system needs the original .msu or .cab file to reverse the changes. If that file got deleted by Disk Cleanup or a tool like CCleaner, the uninstaller can't proceed and throws this error.

The fix — two methods

Skip the graphical uninstaller. It's not going to work. You need to go deeper.

Method 1: Use DISM to remove the update (works for most cumulative updates)

Open an administrative Command Prompt. Press Win + X, select Terminal (Admin) or Command Prompt (Admin).
List all installed updates to find the exact package name:
```
dism /online /get-packages /format:table
```
Look through the output for the update you want to remove. The package name looks like Package_for_RollupFix~31bf3856ad364e35~amd64~~22621.1.1.7. Copy the full name.

Remove it with:

dism /online /remove-package /packagename:Package_for_RollupFix~31bf3856ad364e35~amd64~~22621.1.1.7

If DISM reports "The operation completed successfully", reboot. If it gives you "Error: 0x800f0826" or 0x800f0900, the package really is marked as permanent, and you'll need Method 2.

Method 2: Use WUSA with the permanent flag bypass (for stubborn updates)

WUSA is the underlying installer for .msu files. It normally respects the permanent flag, but you can force it off with a registry tweak that makes Windows treat the update as removable. This is the nuclear option — only do it if you're sure you want this update gone.

Open Regedit as Administrator.
Navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Component Based Servicing\Packages
Press Ctrl + F and search for the update KB number (e.g., KB5034441). You'll find a key like Package_for_RollupFix~31bf3856ad364e35~amd64~~22621.1.1.7.
Inside that key, look for a DWORD value named InstallClient. Change its value from 1 to 0. If it doesn't exist, create it as a DWORD (32-bit) and set it to 0.
Close Regedit, then run the DISM command from Method 1 again. This time it should work.
Reboot.

Still failing? Here's what to check

Is the update a driver? Go to Device Manager, find the device, right-click, select Properties > Driver > Roll Back Driver. That's the proper way to undo a driver update — the Settings uninstaller often can't handle them.
Is it a firmware update? Those can't be uninstalled at all via Windows. You'd need to reflash the BIOS/UEFI with an older version from the manufacturer's site. That's a separate process entirely.
Did you run Disk Cleanup recently? Check C:\Windows\SoftwareDistribution\Download and C:\Windows\WinSxS. If those are empty or have been compressed, the uninstaller literally has nothing to work with. The only fix here is a system restore point or a repair install of Windows.

One last thought: if none of this works, ask yourself if you really need to remove the update. Security updates are called that for a reason — uninstalling them leaves your machine vulnerable. Only proceed if the update is causing a genuine problem (boot failure, driver conflict, app crash). If you're just reclaiming disk space, there are safer ways to do that.