How to fix Windows 100% Disk Usage causing slow performance on Windows 10/11

Summary

This guide helps you troubleshoot and resolve: How to fix Windows 100% Disk Usage causing slow performance on Windows 10/11. Follow the steps below to fix the issue.

Common Causes

When your disk usage reaches 100%, Windows may become unresponsive, applications may freeze, and your overall system performance will drop significantly. This is often caused by background processes, outdated drivers, or corrupted system files. If you have already checked if your computer is running slow due to other factors, follow these steps to analyse and resolve high disk usage.

Quick Fix Steps

Before diving into deep system changes, try these immediate actions to see if the disk usage drops:

• Restart your computer: This clears temporary cache and stops runaway processes.
• Check for Windows Updates: Go to Settings > Windows Update > Check for updates. An update stuck in the background often causes high disk activity.
• Close unnecessary apps: Use Ctrl + Shift + Esc to open Task Manager and end tasks that are consuming high disk resources.

Detailed Instructions

1. Analyse the Cause via Task Manager

To fix the issue, you first need to identify which process is responsible for the disk load.

1. Press Ctrl + Shift + Esc to open Task Manager.
2. If the window is small, click More details at the bottom.
3. Click the Disk column header to sort processes by the highest usage.
4. Identify the process at the top. Common culprits include System, Service Host: Local System, or Antimalware Service Executable.

2. Disable SysMain (formerly Superfetch)

SysMain is designed to preload applications into memory, but on some systems (especially those with older HDDs), it can cause constant 100% disk usage.

1. Press Win + R, type services.msc, and press Enter.
2. Scroll down to find SysMain.
3. Right-click SysMain and select Stop.
4. Right-click it again, select Properties, change the Startup type to Disabled, and click OK.

3. Run a Disk Check (chkdsk)

Physical errors or file system corruption on your drive can force Windows to repeatedly attempt to read a sector, causing the disk to spike to 100%.

1. Type cmd in the Windows search bar.
2. Right-click Command Prompt and select Run as administrator.
3. Type the following command and press Enter: chkdsk.exe /f /r
4. You will be asked if you want to schedule the volume to be checked the next time the system restarts. Type Y and press Enter.
5. Restart your computer and allow Windows to analyse and repair the drive.

4. Reset Virtual Memory

If your virtual memory (paging file) is misconfigured or corrupted, it can lead to excessive disk writing.

1. Search for View advanced system settings in the Start menu and open it.
2. Under the Advanced tab, in the Performance section, click Settings.
3. Go to the Advanced tab and click Change under the Virtual memory section.
4. Uncheck Automatically manage paging file size for all drives.
5. Select your C: drive, choose No paging file, and click Set.
6. Restart your computer, then return to this menu and select System managed size to reset the file.

Troubleshooting Persistent Issues

Dealing with Application Freezes

If you notice that specific software is triggering the disk spike, you may be experiencing applications freezing or crashing. Try updating the specific software or reinstalling it to clear corrupted local data.

Checking for Malware

Some malicious software performs heavy background read/write operations (such as cryptomining or data exfiltration). Run a full system scan using Windows Security or your installed antivirus software.

When to suspect Hardware Failure

If you have followed all the steps above and the disk usage remains at 100% or you hear clicking sounds coming from your computer, your drive may be failing. This can sometimes lead to a Blue Screen of Death (BSOD).

If you suspect hardware failure or cannot resolve the issue, please Open a Ticket for further technical assistance.

Still Having Issues?