PC My PC Is Slow Since the Last Update: Patch Tuesday Problems
The morning after Patch Tuesday, it is easy to worry something has broken. Your PC worked fine yesterday, and today apps crawl, the fan runs, and the mouse seems to lag behind every click.
Many PCs are still finishing update work in the background after an update, and that work ends on its own if you give it time. If your PC is still slow after that work has finished, try the fixes on this page first, and use the linked uninstall route only if they do not help.
Timing decides which path is right, so please do not remove an update or run a cleaner tool in the first hour. Give the PC time to finish, then work through the checks below in order if the slowdown stays.
Part of the Windows Update Problems: Stuck, Failed and Slow Updates Fixed Safely series, the pillar guide for this cluster.
Is your PC still finishing the update in the background?
After a monthly Patch Tuesday update, Windows often keeps working after the desktop comes back. It may still be setting up files, checking apps, and running a virus scan. That work uses the disk and the processor, so apps open slowly, pages load late, and typing or scrolling can lag. The PC feels much worse, even though nothing is broken yet.
Press Ctrl + Shift + Esc to open Task Manager, then select CPU or Disk to sort the list. Look for Windows Update, TiWorker.exe, which is the installer worker, Microsoft Defender Antivirus Service, or Search Indexer near the top. A fan that stays on, a warm case, and a busy disk light, if your PC has one, point the same way.
If you see one or more of those names, give the PC the rest of the day before you try a fix. Leave it on, plugged in, and online, and keep to light, normal use such as mail, browsing, and documents, rather than a large game or video edit. On battery or offline, some of this work pauses, so scans, indexing, and app updates take longer to finish.
Check again after a few hours. The fan should run less, the numbers in Task Manager should fall, and apps should start to respond at their usual speed. This load should ease over hours. If it stays at full load for days, or comes back at full load each morning, waiting has done its work and it is time to move on to the checks below.
Check that the update finished and write down its name
Before you judge the speed, check that the update actually finished. A PC that is still waiting for a restart can feel slow, and the fix steps that follow assume the update is complete. This check takes about two minutes.
Open Settings, select Windows Update, then select Update history. Look at the newest entry at the top. Write down its KB number, which starts with the letters KB, and the date it installed. Keep the note on paper or on your phone, where you can find it again.
Go back to the Windows Update page. If you see a message that a restart is pending, or a Restart now button, save your work and restart the PC. Let the restart finish, sign in again, and give the desktop a few minutes before you check the speed.
If Update history shows that the newest update failed and gives an error code, stop here. Write down that code and follow the link to its error code page for the fix that matches that code, instead of guessing. If the update shows as installed, keep its KB number handy for the steps ahead.
Rule out a full disk and one app using all the power
An update can get the blame for a problem that started at the same time for a different reason. Open Task Manager while the PC feels slow by pressing Ctrl + Shift + Esc, and select More details if you see a short list. Select the CPU, Disk, and Memory column headings in turn to sort by each one.
Look for one app of yours near the top, such as your browser with many tabs open. Note the app name and which column it leads, then close it normally and wait a minute. If the PC speeds up, that app, not the update, was using most of the power. Open it again later to see if the problem returns with it.
Next, open File Explorer and select This PC. Look at the bar under your system drive, usually Local Disk (C:). If the bar is red or the drive is nearly full, write that down. A drive with very little free space can slow Windows on its own, even when an update installed without a fault. Keep that note with the KB number you wrote down earlier.
Last, notice where the lag happens. Slowness only in one app, while the Start menu, Settings, and File Explorer respond normally, points away from the update. Slowness everywhere, with no single app at the top and space left on the drive, is the pattern to carry into the next fixes.
Safe fixes to try, in order, once the update has finished
Start these fixes only after the background work above has eased and the update shows as installed. Work through them in order, and test the PC after each one. If speed comes back, stop there.
- Restart the PC in full. Select Start, then Power, then Restart, not Shut down. On many PCs Shut down leaves part of Windows saved for a faster start, while Restart clears it and loads Windows fresh. When the desktop returns, sign in, wait for apps to open, and use the PC for 15 minutes before you judge the result.
- While the PC is plugged in, check the power mode. Open Settings, then System, then Power and battery, and if the power mode is set to Best power efficiency, change it to Balanced. Leave the PC plugged in while you test, since a laptop on battery may run slower by design to save charge.
- Review startup apps in Task Manager. Press Ctrl + Shift + Esc, select Startup apps, and look for entries you recognize that you do not need at sign-in, such as a game launcher or a chat app. Right-click one entry, select Disable, then restart and test again. Leave entries you do not recognize alone.
- Check Windows Update once more. Open Settings, then Windows Update, then Check for updates, and install any follow-on update or driver update Microsoft has since released. A later update sometimes fixes a problem in the first one. Restart again when Windows asks, even if you restarted earlier, then test the PC for another 15 minutes.
Skip any paid speed up, cleaner, or driver updater tool offered along the way. These tools add cost, often change settings you did not ask them to change, and can make a slow PC worse. Windows already has the update and startup controls used above, and none of the steps on this page needs a paid program.
When the slowdown points to a bad update
If all three signs line up, the update itself is the likely cause. The slowdown began right after the KB you wrote down earlier was installed. It returns every time you start the PC, after the background work has eased. It stayed after you worked through the safe fixes in order. You feel it across Windows, not in one app alone.
That timing matters. A slow PC before the update, or slowness only in one app, points to something else. A one-time slow start during background work also does not fit. The pattern above is different because the change is tied to one update and it does not clear with time or with the basic fixes. One sign on its own is not enough.
At that point, use the linked guide to uninstalling a bad Windows update to remove that KB. Have the number ready when you go. Then use the linked guide to pausing Windows updates, so Windows does not install the same update again at once while you test the PC. If the PC runs normally without that update, you have a clear answer about the cause.
Removing an update can also remove a security fix, so check the when not to remove list on the uninstall page before you start. That check comes first. If your case appears on that list, leave the update in place.
If your PC is still slow after three days
If the PC is still slow three days after the update, this is no longer the normal waiting period. If the lag is getting worse, back up your photos and documents first, before any deeper repair is tried. Copy them to a USB drive or external drive, and check that the copies open.
Keep a short note ready for any further help. Write down the KB number you saved earlier, any error code you have seen, and whether the lag happens all the time or only at start up. Add the date the slowdown began.
From here, follow the link to the Safe Mode guide to test Windows with only its basic parts running. If you have an error code, go to the page for that code instead. Those pages give the next steps for each route.
This page is checked again in the monthly Patch Tuesday refresh. If a later update fixes this kind of slowdown, the note at the top will say so.
Conclusion
Timing is the decision on this page. If the slowdown eased as the background work finished, there was nothing to remove. If it stayed, came back at every start, and held on after the safe fixes, treat it as a fault linked to that update.
That order protects you either way. You avoid removing a security fix for a temporary slowdown, and you still have a clear next step if the problem lasts. Keep your note of the KB number and the date, and follow the link that matches what your PC actually did.