How to Fix High Disk Usage in Windows 10

High disk usage in Windows 10 can make your PC feel sluggish, with programs taking forever to open and the system freezing. This guide provides step-by-step fixes to identify and resolve the most common causes, from Windows Search issues to faulty drivers, helping you restore normal performance.

What You’ll Need

Administrator access to your Windows 10 PC
Patience – some steps require waiting for scans or restarts

Step-by-Step

Identify the culprit in Task Manager. Press Ctrl + Shift + Esc to open Task Manager. Click “More details” at the bottom if you see a simplified view. Go to the “Processes” tab and click the “Disk” column header to sort by disk usage. Note which processes are using the most disk – common offenders include System, Windows Search, Microsoft Edge, or Antivirus.
Restart your PC. This clears temporary files and stops background processes that may be stuck. Save your work and restart before trying more complex fixes.
Run a disk check. Open File Explorer, right-click your system drive (usually C:), select “Properties”, go to the “Tools” tab, and click “Check” under Error checking. Follow the prompts to scan and repair drive errors. This can fix corruption that causes high disk usage.
Disable Windows Search indexing. If “Windows Search” or “SearchIndexer” is using high disk, disable it temporarily. Press Win + R, type services.msc, and press Enter. Find “Windows Search” in the list, right-click it, select “Properties”, set “Startup type” to “Disabled”, and click “Stop”. (You can re-enable it later if needed.)
Disable Superfetch (SysMain). In the same Services window, find “SysMain” (or “Superfetch” on older versions). Right-click, select “Properties”, set “Startup type” to “Disabled”, and click “Stop”. This service preloads apps into memory but can cause high disk usage on some systems.
Update or roll back drivers. Outdated or buggy drivers, especially storage and chipset drivers, can cause high disk usage. Press Win + X and select “Device Manager”. Expand “Disk drives” and “Storage controllers”. Right-click each device and select “Update driver”, then “Search automatically for drivers”. If the issue started after a recent update, try “Properties” > “Driver” > “Roll Back Driver”.
Run the Windows Performance Troubleshooter. Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters. Select “Performance” and run it. This can automatically find and fix issues that slow down your system.
Check for malware. Run a full scan with Windows Defender (or your preferred antivirus). Go to Settings > Update & Security > Windows Security > Virus & threat protection > Scan options, and select “Full scan”. Malware can cause unusual disk activity.
Disable startup programs. In Task Manager, go to the “Startup” tab. Disable any programs you don’t need at startup by right-clicking and selecting “Disable”. Fewer background programs mean less disk activity.
Adjust virtual memory. If your RAM is low, Windows uses the disk as virtual memory, increasing disk usage. Press Win + R, type sysdm.cpl, and press Enter. Go to the “Advanced” tab, under Performance click “Settings”, then the “Advanced” tab. Under Virtual memory, click “Change”, uncheck “Automatically manage paging file size”, select “Custom size”, and set both initial and maximum size to 1.5 times your RAM (in MB). For example, 8GB RAM = 12288 MB. Click “Set” and restart.
Reset Windows (as a last resort). If nothing else works, go to Settings > Update & Security > Recovery > Reset this PC. Choose “Keep my files” to reinstall Windows without losing personal files, but back up important data first.

Common Mistakes

Disabling Windows Search permanently – This breaks search functionality. Only disable it temporarily to test, and re-enable it later if the issue is resolved.
Killing system processes in Task Manager – Ending “System” or “Windows Explorer” can cause crashes or instability. Only end processes you recognize as third-party apps.
Skipping the restart – Many disk usage issues are transient, and a simple restart clears them. Don’t jump to complex fixes without trying this first.
Disabling Superfetch without testing – On some systems, Superfetch improves performance. Disable it only if you’ve confirmed it’s causing high disk usage, and be ready to re-enable it if system performance worsens.

Tips

Use a solid-state drive (SSD) – If you’re still using an HDD, upgrading to an SSD dramatically reduces disk usage and improves overall speed.
Keep Windows updated – Microsoft regularly patches bugs that cause high disk usage. Check Settings > Update & Security > Windows Update.
Monitor disk usage over time – Use Task Manager’s Performance tab to watch disk activity. If it’s consistently at 100% even when idle, there’s a deeper issue.
Clean up temporary files – Use Disk Cleanup (search for it in the Start menu) or Settings > System > Storage > Temporary files to remove junk that can slow down disk operations.

Troubleshooting

If the steps above don’t fix the issue, try these additional checks:

Check for disk errors in Event Viewer. Search for “Event Viewer”, go to Windows Logs > System, and look for disk-related errors (source: “disk” or “NTFS”). These can indicate hardware failure.
Run a memory test. Faulty RAM can cause excessive disk paging. Search for “Windows Memory Diagnostic” and run it.
Check if the problem occurs in Safe Mode. Restart your PC, hold Shift while clicking “Restart”, then choose Troubleshoot > Advanced options > Startup Settings > Restart, and press 4 for Safe Mode. If disk usage is normal in Safe Mode, a third-party driver or startup program is the cause.
Consider hardware failure. If you hear clicking sounds from your hard drive or the disk check reports uncorrectable errors, back up your data immediately and replace the drive.

Frequently Asked Questions

Why is my disk at 100% even when idle?

Windows performs background tasks like indexing, defragmentation, and updates even when you’re not using the PC. These can cause temporary spikes. If it’s constant, check for malware or a failing drive.

Is it safe to disable Superfetch?

Yes, it’s safe to disable Superfetch. It’s a caching feature that can cause high disk usage on some systems. Re-enable it if you notice slower app launches.

Will disabling Windows Search break Cortana?

Disabling Windows Search will prevent Cortana from searching files and the web. You can still use basic search in File Explorer, but it will be slower.

How do I know if my hard drive is failing?

Signs include clicking or grinding noises, frequent crashes, and disk errors in Event Viewer. Use the disk check tool (Step 3) to see if it reports bad sectors.

Can high disk usage damage my computer?

Not directly, but it can cause overheating and excessive wear on the drive, potentially shortening its lifespan. It’s best to resolve it promptly.

Should I defragment my HDD to fix high disk usage?

Defragmenting an HDD can help performance, but it’s not a fix for high disk usage caused by software issues. Windows automatically defragments on a schedule. Avoid defragmenting SSDs.

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

More in this bed

The whole Tech How-To bed →