How To Fix 100% Disk Usage in Windows 10/11 (2026 Working Method)

If your Windows PC is showing 100% disk usage in Task Manager and your system feels extremely slow, freezes randomly, or takes too long to open programs, you’re not alone. This is a very common issue, especially on systems using HDD drives.

In this guide, I will show you safe and effective methods to reduce or completely fix the 100% disk usage problem in Windows.

You can also watch the full video tutorial below for a visual guide.

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Why Does 100% Disk Usage Happen?

High disk usage usually happens because of:

• Background Windows services

• Corrupted system files

• Bad sectors on the hard drive

• Too many startup applications

• Frequent background optimization

Let’s fix it step by step.

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Method 1: Disable SysMain Service

SysMain (formerly Superfetch) runs in the background and preloads applications into memory. On low-end systems or HDD drives, it can cause very high disk activity.

Steps:

1. Press Windows + R2. Type:3. services.msc4. Click OK5. Press S to jump to services starting with S6. Find SysMain7. Right-click → Select Properties8. Change Startup type to Disabled9. Click Apply and then OK10. Right-click again, Click Stop

Benefits:

• Reduces background disk usage• Improves system responsiveness• Safe for most users

There is no major risk in disabling this service.

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Method 2: Disable Connected Devices Platform Service

This service manages device communication and syncing features. Most users don’t need it constantly running.

Steps:

1. In the same Services window2. Find Connected Devices Platform Service3. Right-click → Click Stop4. Open Properties5. Set Startup type to Disabled6. Click Apply and OK

Benefits:

• Reduces unnecessary background processes• Helps lower disk usageIt is generally safe to disable unless you rely heavily on device syncing features.

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Method 3: Optimize the C Drive

Frequent automatic optimization can increase disk usage in the background.

Steps:

1. Open This PC2. Right-click on C Drive3. Click Properties4. Go to the Tools tab5. Click Optimize6. Make sure Scheduled Optimization is turned OFF

Benefit:

• Reduces automatic background disk activity• Gives better manual control

This step is especially helpful for HDD users.

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Method 4: Run CHKDSK Command (Very Important)

Corrupted files and bad sectors are common causes of 100% disk usage. Running CHKDSK can scan and repair these errors.

Steps:

1. Search for CMD2. Right-click → Select Run as Administrator
2. Paste the following command:chkdsk C: /f /r
3. Press Enter
4. When asked to schedule the scan on restart, press: Y
5. Restart your computer

What Happens After Restart?

• Windows will scan the drive• It will check for file system errors• It will detect bad sectors• It will automatically fix issues if possible

The process may take some time depending on your drive size. Do not turn off your PC during this process.

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Method 5: Disable Unnecessary Startup Apps

Too many startup programs increase background usage and slow down your system.

Steps:

1. Press Ctrl + Shift + Esc2. Open Task Manager3. Go to the Startup tab4. Disable apps you don’t need at startup

You can enable them again anytime later.

Benefits:

• Faster boot time• Lower background disk activity• Better overall performance

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Final Words

By following all the methods above, you should be able to significantly reduce or completely fix the 100% disk usage problem in Windows.

If the issue still persists, your hard drive may be physically damaged and replacing it with an SSD is highly recommended for better performance.

If this guide helped you, consider sharing it with others who might be facing the same issue.