Problems · Slowness
Why is my PC slow after a Windows update?
For the first day after a large Windows update, slowness is normal: the system rebuilds its search index, re-optimises apps, and finishes installing in the background. Leave the PC on and plugged in for a few hours and most of it clears. If it is still slow after a day and a restart, the update most likely brought a graphics or chipset driver that behaves worse than the one before, and rolling that driver back is the fix.
Less often, an update re-enables startup programs you had turned off, resets a power plan to Balanced, or leaves a failed install retrying. Each of those has a quick check below.
First, notice when it happens
The causes, ranked
1. The update is still finishing in the background
most commonHow to confirm it
Task Manager shows Windows Update, the search indexer, or a process named for servicing or optimisation near the top of CPU and Disk. Windows Update may still show a restart pending.
The fix
Restart if asked, then leave the machine on and idle for a few hours. Do not power it off during that time. The slowness clears on its own.
2. A graphics driver that came with the update
commonHow to confirm it
Device Manager shows a new driver date for the display adapter, and the slowness shows in games, video and scrolling more than anywhere else.
The fix
Install the current driver from the card maker's own site rather than the one Windows delivered, choosing a clean install. If it began with a specific version, roll back to the previous one from Device Manager.
3. Startup programs re-enabled or a power plan reset
commonHow to confirm it
Task Manager's Startup tab shows entries enabled that you had disabled, or the power plan in Settings is back to Balanced or Power saver.
The fix
Disable the startup entries again and set the power mode to Best performance. Both are one-click changes and both survive the next update better if set from Settings rather than a maker's utility.
4. A failed update retrying
occasionalHow to confirm it
Windows Update shows the same update failing repeatedly, and disk usage rises every time it tries.
The fix
Run the Windows Update troubleshooter from Settings, restart, and try again. If it keeps failing, install the update by hand from the Microsoft Update Catalog, which bypasses the stuck download.
5. A chipset or storage driver changed how the machine manages power
occasionalHow to confirm it
The processor no longer reaches its previous speeds under load, or drive access became slower, immediately after the update. Nothing in Task Manager is obviously busy.
The fix
Update the chipset and storage drivers from the board or PC maker's site, which are usually newer and better matched than the generic ones an update installs.
6. The system drive ran out of space during the update
rare but seriousHow to confirm it
Free space on the system drive is under about 10 percent. Large updates keep a copy of the previous version, which can be tens of gigabytes.
The fix
Use Disk Cleanup or Storage Sense to remove previous Windows installations once you are sure the update is working, and keep at least 15 percent free.
Measure it instead of guessing
Run a SystemCheck test before and after rolling a driver back, or after the update settles, and compare the two reports. The CPU stage shows whether the processor holds the same sustained speed it did before, and the GPU stage shows whether the graphics driver delivers frames as evenly. A machine that measures the same but feels slower still has a background process to find; one that measures worse has a driver or power plan change to undo.
What software cannot tell you here
- Which update or driver was installed. A browser cannot read Windows Update history; Settings and Device Manager can.
- Whether the update is still working in the background. Task Manager shows that; the test only sees its effect on the processor.
- Whether a rollback is available. Windows keeps the previous version for a limited time, and only Settings knows how long is left.
Asked, in people’s own words
- How long is a PC slow after a Windows update?
- Usually a few hours, up to a day, while indexing and optimisation finish. If it is still slow after a full day and a restart, the cause is no longer the update itself but something it changed, most often a driver.
- Can I uninstall a Windows update that made my PC slow?
- Yes, for a limited time. In Settings under Windows Update, Update history has an option to uninstall updates, and a major version can be rolled back within about ten days. Try rolling back the graphics driver first, since that is the usual cause and is far less disruptive.
- Why did a Windows update change my graphics driver?
- Windows Update delivers drivers from makers when it thinks they are newer, and its copy is not always the best one for your card. Installing the driver directly from the card maker's site, with a clean install, replaces it with a version tuned for the card.
- Should I stop Windows updates to keep my PC fast?
- No. Updates fix security holes, and a slowdown after one is almost always temporary or fixable with a driver rollback. Pausing updates for a week while a bad driver is corrected is reasonable; disabling them is not.