How to fix high disk usage caused by SysMain (Superfetch) slowing down Windows 11

Performance & Troubleshooting KB-715

Summary

This guide helps you troubleshoot and resolve: How to fix high disk usage caused by SysMain (Superfetch) slowing down Windows 11. Follow the steps below to fix the issue.

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Common Causes

SysMain, previously known as Superfetch, is a Windows service designed to improve system performance by preloading frequently used applications into memory. While helpful on some systems, it can occasionally cause 100% disk usage on Windows 11 PCs, leading to slow response times and sluggish performance. This guide walks you through disabling or adjusting SysMain to resolve high disk activity.

Quick Fix Steps

Open the Run dialog by pressing Windows key + R.
Type services.msc and press Enter.
Locate SysMain in the list.
Right-click SysMain and select Properties.
Set Startup type to Disabled.
Click Stop, then click OK.
Restart your computer.

Detailed Instructions

Step 1: Open the Services Console

Press Windows key + R on your keyboard to open the Run box. Type services.msc and press Enter. The Services window will open, displaying a list of all background services running on your Windows 11 device.

Step 2: Locate SysMain

Scroll through the list until you find SysMain. The list is alphabetical, so it should appear near the top under "S".

Step 3: Open SysMain Properties

Right-click SysMain and select Properties from the context menu. A properties dialog box will appear.

Step 4: Change the Startup Type

In the Properties window, look for the Startup type dropdown menu. Click the dropdown and select Disabled.

Step 5: Stop the Service

Under Service status, click the Stop button. Once the service has stopped, click OK to save your changes.

Step 6: Restart Your Computer

Restart your Windows 11 PC to ensure the changes take effect. After rebooting, check Task Manager (Ctrl + Shift + Esc) to confirm disk usage has returned to normal levels.

Troubleshooting

If Disk Usage Remains High

If disabling SysMain does not resolve the issue, consider the following:

Check for pending Windows updates via Settings > Windows Update.
Run a full antivirus scan to rule out malware causing disk activity.
Check your drive health using chkdsk or the manufacturer's diagnostic tool.
Review other high-disk processes in Task Manager.

Re-enabling SysMain

If you notice slower application launch times after disabling SysMain, you can re-enable it by following the steps above and setting Startup type back to Automatic, then starting the service.

Disabling SysMain is safe and will not harm your Windows installation. It simply stops Windows from preloading applications into memory.

Avoid disabling multiple system services at once, as this can cause system instability. Only disable SysMain unless advised otherwise by a technician.

If you continue to experience high disk usage or system performance issues, please Open a Ticket with our Brisbane support team.

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Still Having Issues?

Need more help? If the issue persists after trying these steps, please open a support ticket and our team will assist you.

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