Windows 11 KB5048667 is turning out to be a disaster for some people, and we can confirm that there’s an issue where the update could fail to install. It’s also making some PCs run slower than usual, and we think it’s related to a bug with the CPU scheduler in the Windows 11 Patch Tuesday.
Dozen and more users are reaching out to me with complaints of Windows 11 KB5048667 installation issues. In some cases, it’s also causing severe performance issues. First, let’s talk about the installation issues with Windows 11 24H2 December 2024 Patch Tuesday, and then I’ll talk about the performance issues.
According to reports received by Windows Latest and confirmed in our tests in a virtual machine, Windows update fails with error 0x800f081f when installing the KB5048667 update. One user explained that the patch is also very slow to start, with the message “Downloading – 0%” displayed for a long time.”
“I have a fast internet connection. It then starts installing, but fails at 100%. I was instructed by the Windows update troubleshooter to make this problem report, it found a problem and said it had been corrected, but apparently not, so far, unfortunately,” one of the affected users noted.
Our friends with MacBook have also reported running into installation error like 0x80070302 when they try to install Windows 11 24H2 patch on M3 using Parallels.
“I previously reported this under an earlier update, but I’m still getting the same error when trying to install the latest Windows 11 24H2 update for ARM64,” they added.
“All the updates failed on my PC, even KB5046740 got stuck at 40%,” another user told Windows Latest. “KB5048667 will not install for me… remains ‘pending restart.’
Some of the folks tried manual installations and reinstalls of Windows, but nothing worked.
In some cases, we also observed that Windows Update could take longer than usual to download or even install the patch, only to fail at the last moment.
Performance issues with Windows 11 KB5048667
Even when the update does install, some of you might run into performance issues with the Windows 11 December 2024 update.
Some of our readers have noticed that after installing the Windows 11 KB5048667 update for Windows 11 24H2, CPU performance isn’t the same as before. We’ve seen reports from users saying that their PCs run smoothly at first, but then, after some time, their processor starts slowing down.
You may even find your games stuttering or your system feeling more sluggish than usual, especially if it’s been running for a while since the last restart.
We’ve also heard from people who say a simple reboot brings things back to normal, at least for a little while. Unfortunately, the problem tends to return after the system stays on for a bit.
There are suspicions that Windows might now be managing CPU power in a way that places your games or apps into a low-performance mode, even when they shouldn’t be. We fear there’s a problem with the CPU scheduler post Windows 11 KB5048667.
If you’re experiencing these issues, you might try rolling back to a previous Windows version, changing your power settings, or even using tools like Process Lasso.
Here’s what you can try doing:
- Disable Fast Boot or adjust the way Windows handles CPU cores.
- Reinstall the update.
- Uninstall the update from Settings > Windows Update > Update History > Uninstall update.
Windows Latest understands that there’s no one-size-fits-all solution for just yet, and it may take another official update or patch to fully resolve these slowdowns. For now, if performance is really important to you, you might consider holding off on the KB5048667 update.
Here’s a list of other problems:
- Higher CPU temperature than normal by about 4/5 degrees.
- No fix for slightly lower performance in 3D applications/games.
- Explorer options fly off screen when maximized.
- Netflix and Prime Video apps lagging and looping in full screen.
Windows 11 24H2’s long-standing issues, such as File Explorer’s menu options not showing up correctly when the window is maximized. In addition, apps like Netflix and Prime Video have playback problems, especially when viewing content in fullscreen mode.