📎 AI Summary:
The thread is about a user who upgraded to Windows 11 25H2 and then noticed their PC felt significantly slower, particularly confused by Windows Update showing 25H2 as both “installed” and “available.” The replies explain that this UI can happen because 25H2 being installed refers to the feature version, while Windows Update may still be offering a later cumulative/quality update for that same version; suggested fixes include installing the pending update, running system checks (SFC/DISM), rebooting, and monitoring background activity, with rollback noted as potentially possible for a limited time. Overall sentiment is helpful and reassuring, treating the slowness as likely temporary post-upgrade behavior rather than an outright failure.
musicmaster

musicmaster

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I saw that 25H2 was available and installed it. And now I regret it because my installation has become a lot slower.

When I look in the control panel under Windows Update the information is confusing. It says that 25H2 is installed but it also says that it is available for installation.
Dutch Windows Update: PC updated, 2025‑10 cumulative update for Windows 11 available.
 

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WindowsForum AI
Hi musicmaster — sorry the 25H2 upgrade made your PC feel slower. The screenshot helps a lot. Quick answer first, then concrete troubleshooting and rollback options.
Short explanation of what you’re seeing in Windows Update
  • The message doesn’t mean the feature update wasn’t installed. It means: the feature update (Windows 11, version 25H2) is on the PC, and Windows Update is now offering a cumulative update (KB5070773 in your screenshot) that applies to 25H2. So “25H2 is installed” and “25H2 updates are available” can both be true at the same time — one is the feature update, the other is a later cumulative/quality update for that same version.
What I recommend you do (in this order)
  • Install the pending cumulative...
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WindowsForum AI

WindowsForum AI

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#2
Hi musicmaster — sorry the 25H2 upgrade made your PC feel slower. The screenshot helps a lot. Quick answer first, then concrete troubleshooting and rollback options.
Short explanation of what you’re seeing in Windows Update
  • The message doesn’t mean the feature update wasn’t installed. It means: the feature update (Windows 11, version 25H2) is on the PC, and Windows Update is now offering a cumulative update (KB5070773 in your screenshot) that applies to 25H2. So “25H2 is installed” and “25H2 updates are available” can both be true at the same time — one is the feature update, the other is a later cumulative/quality update for that same version.
What I recommend you do (in this order)
  • Install the pending cumulative update
  • Click “Downloaden en installeren” (Download and install) for the KB shown in your screenshot, reboot when prompted. Many post-upgrade performance problems are fixed by the first cumulative update after a feature upgrade.
  • Check your exact installed version and build
  • Press Windows key + R, type winver and press Enter. Tell me the “Version” and “OS build” lines that appear (or copy a screenshot). This confirms exactly what is installed and whether the KB was applied.
  • Check Task Manager for real bottlenecks
  • Open Task Manager (Ctrl+Shift+Esc) → Processes tab. Sort by CPU, Disk and Memory to see which process is using the system heavily. Also open Startup tab to disable anything unnecessary from starting.
  • If you see a process using lots of disk (SearchIndexer, OneDrive, Antimalware Service, etc., tell me what it is.
  • Common quick fixes to try now
  • After installing the KB and rebooting, let the PC sit idle for 15–30 minutes (Windows often finishes background indexing, optimization and driver installs after an upgrade).
  • Pause OneDrive sync temporarily (if you use OneDrive) while testing.
  • Run a quick SFC/DISM health check:
  • Open an admin Command Prompt and run:
  • sfc /scannow
  • DISM /Online /Cleanup-Image /RestoreHealth
  • Reboot after those finish.
  • Try a Clean Boot to rule out third‑party software
  • Press Windows key, type msconfig → Services tab → check “Hide all Microsoft services” → click Disable all → open Task Manager → Startup tab → disable third-party startup items → Restart. Test performance. If it’s fixed, re-enable services/startup items one at a time to find the culprit.
  • Check device drivers and storage health
  • Open Device Manager and look for devices with yellow exclamation marks. Right-click major devices (display, storage controller, network) → Update driver or visit the vendor’s website for the latest driver.
  • If you have an HDD, check Disk health (CrystalDiskInfo or built-in Manufacturer tool). If it’s an SSD, ensure firmware and TRIM are OK.
  • Check whether Windows is still doing background tasks
  • Indexing rebuild, SearchIndexer activity, “device optimization”, and Windows Update background installs can cause temporary slowness for several hours after a feature upgrade. Resource Monitor can show I/O waits.
If you want to roll back to the previous Windows version
  • There’s a built-in rollback option for a short time after a feature update (by default 10 days).
  • Settings → System → Recovery → “Go back” (or “Go back to the previous version of Windows”) — if that option is present you can use it. Follow the prompts and keep PIN/password handy.
  • Important: If you used Disk Cleanup or Storage Sense and removed “Previous Windows installation(s)” (the Windows.old files), rollback won’t be available.
  • If rollback isn’t available and you want to go back, the safe way is to restore from a full image backup or reinstall the old version manually (I can guide you through creating installation media and doing a reinstall if needed).
What I need from you to continue
  • Tell me what winver reports (Version and OS build).
  • After you install that KB and reboot, tell me whether things improved.
  • If still slow: open Task Manager → Processes and report which process(es) show highest CPU/Disk usage (name and %). Also tell me whether your system disk is an SSD or HDD and approximate age/specs (CPU/RAM).
If you want, I can give step‑by‑step commands for SFC/DISM, how to use Resource Monitor, and the exact rollback/check-for-Windows.old steps. Which would you like me to provide next?
 

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Popcorn8892

Popcorn8892

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#3
musicmaster said:
I saw that 25H2 was available and installed it. And now I regret it because my installation has become a lot slower.

When I look in the control panel under Windows Update the information is confusing. It says that 25H2 is installed but it also says that it is available for installation.
Click to expand...
The 25H2 update is supposed to be just an enablement package, meaning the download is minimal and the update is more or less instantaneous. Some people have done this since last month. The message you see now is probably the real update for this month.

I would suggest you:
  1. Update for this month.
  2. If it's still slow, reboot.
  3. Run the 2 system utilities that can fix many problems, starting with cmd in admin mode:
sfc /scannow​
DISM /Online /Cleanup-Image /RestoreHealth​
 

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