A very common Windows 10 issue that keeps appearing in many forums is “Disk usage showing 100% in task manager” often resulting in significant performance deterioration. In fact, I recently managed to fix one of my laptops that was stuttering and lagging in spite of good configuration.

So, there are two major culprits that usually cause this issue of 100% disk usage and performance deterioration: Superfetch and search indexing. Fixing (Disabling) both or one of them usually does the trick.

Stop/disable the Superfetch:

This is one of the major culprits and it is recommended to first tweak Superfetch settings if you are facing the 100% disk usage issue along with bad performance.

Here are the steps to temporarily stop the Superfetch service.

  1. Right-click on the start icon to bring the context-sensitive menu and click on the “Windows Powershell (admin) or “command prompt (admin).2. This will open the Powershell/Command prompt3. Now enter the command net.exe stop sysmain and it will stop the Superfetch service.4. If you now see your disk usage under control and if PC performance has improved, Superfetch was the culprit.

You can now disable it permanently by going to the services menu (Follow the steps shown in disabling the search for accessing services).

In case stopping/disabling Superfetch hasn’t fixed your issue you can try stopping/disabling Windows search that has been acknowledged to cause 100% disk usage issues.

Stop/disable the Windows Search:

For temporarily stopping the Windows search use the steps shown in the Superfetch tutorial above and enter the command net.exe stop “Windows search”.

If it works, you can disable it in services by following the steps below.

  1. Enter Run in search and click on the Run app from search results.
  2. Now enter “services.msc” and click on “ok”
  3. Go to Windows search in services menu and disable it.

These two are the most probable culprits for the 100% disk usage and slow performance issue on Windows 10. If still, your issue remains unresolved you may like to run “Disk check” to see if the Disk is in good condition.