How to Fix 100% Disk Usage in Windows (2025 Guide)

Before troubleshooting, confirm if your disk usage is really at 100%:

1. Press Ctrl + Shift + Esc to open Task Manager.
2. Click on the Processes tab.
3. Look at the Disk column—if it shows 100% usage, continue with the fixes below.

Windows has a background service called SysMain (formerly Superfetch) that preloads frequently used apps, but it can cause high disk usage.

1. Press Win + R, type services.msc, and press Enter.
2. Scroll down to find SysMain.
3. Right-click → Properties and set Startup type to Disabled.
4. Click Stop and then Apply → OK.

🔹 Why this works? It prevents Windows from aggressively preloading apps, reducing disk load.

Windows Search Indexing can cause constant disk activity, especially on HDDs.

1. Press Win + R, type services.msc, and press Enter.
2. Find Windows Search, right-click it, and select Properties.
3. Change Startup type to Disabled.
4. Click Stop, then Apply → OK.

🔹 Why this works? Disabling indexing prevents Windows from continuously scanning files, freeing up disk usage.

Too many apps launching at startup can cause high disk usage.

1. Open Task Manager (Ctrl + Shift + Esc).
2. Go to the Startup tab.
3. Right-click unnecessary apps and select Disable.

🔹 Why this works? Fewer startup apps mean faster boot times and lower disk usage.

Outdated drivers and system bugs can cause disk usage problems.

1. Press Win + I to open Settings.
2. Go to Windows Update → Click Check for updates.

1. Press Win + X → Select Device Manager.
2. Expand Disk drives, right-click your hard drive, and select Update driver.
3. Do the same for Storage controllers and IDE/ATA controllers.

🔹 Why this works? Updates fix bugs and compatibility issues causing high disk usage.

Windows constantly runs background notifications and tips, increasing disk usage.

1. Press Win + I → Go to System → Notifications & actions.
2. Turn off “Get tips, tricks, and suggestions as you use Windows”.

🔹 Why this works? It stops Windows from constantly checking and displaying unnecessary notifications.

Corrupt system files or disk errors can lead to 100% disk usage.

1. Open Command Prompt as Administrator (Win + X → Command Prompt (Admin)).
2. Type the following command and press Enter:

chkdsk C: /f /r

Type Y, press Enter, and restart your PC.

🔹 Why this works? This scans and repairs bad sectors on your hard drive.

🔍 Step 8: Adjust Virtual Memory (Paging File Size)

If Windows runs out of RAM, it uses the hard drive as virtual memory, which can overload disk usage.
How to Adjust Virtual Memory:

Press Win + R, type sysdm.cpl, and press Enter.

Go to the Advanced tab → Click Settings under Performance.

Click the Advanced tab → Click Change under Virtual Memory.

Uncheck "Automatically manage paging file size".

Set Initial size to 1.5 times your RAM (e.g., 12GB RAM → 18000 MB).

Set Maximum size to 3 times your RAM (e.g., 12GB RAM → 36000 MB).

Click Set → OK → Restart PC.

🔹 Why this works? It prevents Windows from constantly swapping data, reducing disk usage.
🔍 Step 9: Check for Malware & Viruses

Malware and background viruses can overload your disk usage.
How to Scan for Malware:

Open Windows Security (Win + I → Update & Security → Windows Security).

Click Virus & threat protection → Quick Scan.

For a deeper scan, click Scan options → Full scan.

🔹 Why this works? Malware can secretly run in the background, consuming disk resources.
🔍 Step 10: Upgrade to an SSD (Best Solution 🚀)

If you’re using an HDD, switching to an SSD (Solid State Drive) is the fastest way to fix 100% disk usage.
Why Upgrade to an SSD?

✔ Faster boot times (10 seconds vs. 1-2 minutes).
✔ No moving parts = No disk overload issues.
✔ Better performance in opening apps, browsing, and gaming.

💡 Tip: Even a budget SSD (256GB) can make a huge difference in performance!
🚀 Conclusion: Fix 100% Disk Usage & Speed Up Your PC!

If your Windows PC is constantly slow due to 100% disk usage, try these solutions:

✅ Disable SysMain & Windows Search
✅ Limit Startup Programs
✅ Update Windows & Drivers
✅ Run Disk Check & Scan for Malware
✅ Upgrade to an SSD for the best performance boost

💬 Did these solutions work for you? Let us know in the comments! 🎯