100% Disk Usage on windows by system

Question

I know there has been a post about this already in 2019, but my computer is very strong and can handle multiple apps like e..g Roblox, Roblox studio, chrome, 100+ tabs at the same time. 1 day, it just magically failed up to 100% disk usage by system. No other apps that aren't installed by default on windows 11 are taking up many disk usage. Even with a pretty good gaming PC it still happens. How do I fix it?

Answer 1

Hi. I'm David, and I'm happy to help you.

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This behavior can occur for several reasons. It is necessary to investigate.

To better understand, please do the following:

• Open Task Manager (Ctrl + Shift + Esc) in the "Processes" tab. Click on the top of the "Disk" column to sort processes by disk usage.
• Share a screenshot of the current state while high disk usage is occurring. Use the shortcut "Windows + Shift + S" to use the screenshot tool.

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Looking forward to your reply.

Answer 2

High disk usage by System usually means Windows or background apps are heavily reading/writing to the drive. Use these steps to reduce it and improve performance.

1. Free up disk space
   • Low free space can cause constant disk activity.
   • Run Storage Sense:
     1. Select Start > Settings > System > Storage.
     2. Turn on Storage Sense.
     3. Select Configure Storage Sense or run it now (or Run Storage Sense now, depending on version).
     4. Under Free up space now, select Clean now.
   • Remove temporary files manually:
     1. Start > Settings > System > Storage.
     2. Select Temporary files, select items to remove, then Remove files.
   • Use Disk Cleanup:
     1. Select Start, type Disk Cleanup, open it.
     2. Select the system drive and clean recommended items.
2. Uninstall unused apps
   • Fewer installed apps means fewer background services and less disk activity.
   • Windows 11:
     1. Start > Settings > Apps > Installed apps.
     2. For apps not needed, select More options (… ) > Uninstall.
3. Disable startup apps
   • Startup apps can cause heavy disk usage right after sign‑in.
   • Press Ctrl + Shift + Esc to open Task Manager.
   • Select Startup apps.
   • Right‑click unneeded apps and select Disable.
4. Turn off background apps
   • Reduce apps allowed to run in the background.
   • Windows 11:
     1. Start > Settings > Apps > Installed apps.
     2. For an app, select More options (… ) > Advanced options.
     3. Under Background app permissions, set Let this app run in the background to Never.
5. Optimize the drive
   • Fragmented HDDs can show high disk usage.
   • Select Start, type Defragment and Optimize Drives, open it.
   • Select the system drive, then Optimize.
6. Adjust performance settings and power mode
   • Reduce visual effects and allow the system to favor performance.
   • Visual effects:
     1. Select Start, type Adjust the appearance and performance of Windows, open it.
     2. On Visual Effects, select Adjust for best performance.
   • Power mode (Windows 11):
     1. Start > Settings > System > Power & battery.
     2. In Power mode, select Best performance.
7. Monitor which processes are heavy
   • Press Ctrl + Shift + Esc to open Task Manager.
   • On Processes, sort by Disk to confirm that System is the main user and check if any other processes spike disk usage.
   • On Startup apps, disable anything unnecessary (as above).
8. Restart regularly
   • After making changes, restart:
     1. Start > Power > Restart.
   • After restart, open only required apps and watch disk usage in Task Manager.

If disk usage remains at 100% by System after these steps, the next checks (not in the provided guidance) would typically involve driver, disk health, or antivirus issues; consider contacting support if the problem persists.

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References:

• Tips to improve PC performance in Windows