How to Fix 100% Disk Usage in Windows 10

So, you’ve been using your Windows 10 PC for a while, but lately, you’ve noticed that it’s quite sluggish and applications freeze when you launch them. Upon further investigation, you discover that the disk utilization capacity is at 100%! Strange, right?

Well, it does happen, and we’re pretty sure you are at a loss of what to do. When your disk utilization is at 100%, the total sum of the hard disk’s read/write speed has exceeded the 100 -150Mbps threshold.

To fix various Windows 10/11 problems, we recommend Outbyte PC Repair:
This software will repair common computer errors, protect you from file loss, malware damage, hardware failure, and optimise your computer for peak performance. In three simple steps, you can resolve PC issues and remove virus damage:

  1. Download Outbyte PC Repair Software
  2. Click Start Scan to detect Windows 10/11 issues that may be causing PC issues.
  3. Click Repair All to fix issues with your computer's security and performance.
    This month, Outbyte has been downloaded by 23,167 readers.
  Fix: Windows 10 Taskbar not Working

Diagnosing the Problem

Generally, the read/write speed swings between 100 and 150 Mbps. When it exceeds this range, the result is 100% disk utilization, which slows down your system. You can diagnose the problem by launching the Task Manager.

How to Launch Task Manager?

Task Manager is a Windows monitoring tool that gives you a glance at your system’s performance and running applications. The task manager allows you to:

  • View Running applications and services
  • Forcefully close / end running applications
  • View applications’ RAM and CPU utilization
  • View startup programs
  • View system’s performance (RAM, CPU, Disk, and Network)

To access the task manager Press Windows Key + X.

Scroll and click on the ‘Task Manager’ option.

Alternatively, you can right-click on the taskbar and click on the ‘Task Manager’ option as shown below

Fix High Disk Usage in Windows 10

After clicking on the ‘Task Manager’ option, the Task manager window will open.

Analyze Programs in Task Manager

As you can see above, the Disk utilization capacity is at 100% and has a red outline. There are several fixes for this phenomenon, depending on what is causing it. In this article, we’ll dive further into how you can remedy this problem.

  6 Task Manager Alternatives for Windows 10

How to Fix High Disk Usage?

Restart the System

The first fix for every Windows problem is Restarting the device. The Restarting would ensure that any corrupt application which might be the reason for the 100% disk usage would be stopped. To detect the application which is causing the 100% disk usage, you can restart the system in Safe Mode.

Check for Malware Infection

A malware infection could also be the major reason for the slow system performance and the 100% disk usage. After infiltrating your device, malware can hide itself and remain active in the background, thus using the system resources. To detect and remove the malware from the system, you can install a robust antimalware solution like Malwarefox in your system.

Disable SysMain (Superfetch)

SysMain, which was formerly known as Superfetch, is a service that runs in the background in Windows systems – ever since Windows Vista – and quietly analyzes the RAM and applications that your system uses most.

It then preloads frequently used applications into the RAM so that they are loaded much faster with subsequent launches. The drawback to SysMain is that it constantly hogs the CPU and RAM, slowing down applications considerably.

Is SysMain useful? For the most part, yes, but in some cases, you might not need it. For instance, the impact it makes in preloading apps might hardly be noticeable when using an SSD drive. This is because SSD drives are much faster than traditional mechanical drives and so do not need to preload applications.

Is it okay to disable the SysMain service? Absolutely! If your system is ‘hanging,’ it’s safe to proceed. But if all’s well, there’s no need to disable it.

Disable SysMain using Services

  1. Press the Windows Key + R

  2. In the dialogue box that appears, type services.msc in the text field.How to Fix 100% Disk Usage in Windows 10

  3. Press Enter.

  4. The ‘Services’ window will open, displaying all the running services on your PC. Scroll down and locate the ‘SysMain’ option.

  5. Right-click on ‘SysMain’ and select the ‘Stop’ option as shown below.Stop SysMain

This should free up some disk utilization and allow your applications to run seamlessly. To stop it from running on startup follow these steps.

  1. Right-click the program and select ‘Properties.SysMain Properties
  2. Click on the ‘Startup type’ pulldown menu.
  3. Select the ‘Disabled’ option as shown. Disable SysMain
  4. Click on ‘Apply’ then ‘OK’ to effect the changes.
  Fix: Service Registration is Missing or Corrupt in Windows 10
Disable Windows Search

Is your Windows system still running slowly? Don’t fret. You can go ahead and disable the Windows Search service on your system. Windows Search is notorious for increasing the load on the system’s disk.

To temporarily remedy this until the next reboot, take the following steps

  1. Go to the search bar and type ‘Command Prompt’. Run it with Admin Rights.Run Command Prompt as Administrator
  2. Once open type ‘net.exe stop “Windows searchin the command box.How to Fix 100% Disk Utilization in Windows 10

To disable the service permanently, follow these steps

  1. Hit Windows Key + R
  2. In the dialogue box that appears type services.msc.
  3. Scroll down and locate Windows search
  4. Right-click and select PropertiesFix High Disk Usage in Windows 10
  5. In the ‘Startup type’ pull-down menu, click and select ‘Disabled’How to Fix 100% Disk Usage in Windows 10
  6. Click on ‘Apply’ then ‘OK’.
Reset Virtual Memory

Virtual memory is a memory that sits on your hard drive and acts as an extension of RAM. The computer normally uses it when the system is running low on RAM. Windows switches to virtual memory where it temporarily stores files and then swaps them back to the main memory as required. If virtual memory is unnecessarily high, it might cause degradation in your system’s performance.

To reset virtual memory follow below steps:

  1. Navigate to Control Panel -> System and Security and click on System.
  2. Under About scroll down and select Advanced system settings.Advanced System Settings
  3. Click on Settings under the Performance heading.Performance Settings
  4. Under the Advanced tab, click on Change below the Virtual memory heading.Adjust virtual memory
  5. Next, uncheck ‘Automatically manage paging file size for all drives.’uncheck automatically manage
  6. Highlight the System Volume and click on the ‘Custom size’ radio button.VM custom size
  7. Enter your RAM’s size in MB in the ‘initial size’ text field.
  8. ‘Maximum size’ should be 1.5 times the RAM’s size. For instance, for a 4GB RAM size, the maximum size should not exceed 6144 MB (4096 x 1.5).
  Windows 10 Tutorial: Change The Virtual Memory Size
Change Google Chrome Settings

Google Chrome is notorious for hogging RAM and slowing down a system. To circumvent this problem, follow the steps below.

  1. Go to ‘Settings.
  2. Under Privacy and security, click on Cookies and other site data.cookies and other site data
  3. On the next window, scroll down and switch off Preload pages for faster browsing and searching option.Switch off Preload pages
  How to view Data Usage in Windows 10
Purge any Flash Player Updates

Flash Player has a reputation for degrading system performance, leading to a spike in disk usage. Uninstalling flash and flash updates can significantly alleviate the workload on the disks.

  1. Navigate to Settings > Update & Security.
  2. Locate ‘Windows Update.
  3. Go to ‘View your update history.‘
  4. Search for Flash Player updates under ‘Uninstall Updates.’
Fix 100% Disk Usage in Windows 10
  How to Clear Clipboard in Windows 10

Finally, run a chkdsk command to scan and fix issues with your hard drive.

  1. Launch Command Prompt as Admin.
  2. Type chkdsk /f C:
  3. Hit Enter. The system will notify you that the drive is currently in use and will execute the command when you restart the system.
Disable Antivirus

The 100% disk usage problem can also caused by some antivirus programs. It may be because of some faulty update or a corruption by a malicious file. To fix this, you can temporarily disable the antivirus problem and check whether the problem persist. If the problem is fixed, then the antivirus is the culprit. You can either uninstall and re-install it or update it.

  Fix Hard Disk Problems with chkdsk Switches in Windows 10


Ideally, your system should run well below 100% in Disk usage. When all the above fails, this could be an indicator of hardware failure or aging. In that case, we advise you to back up your data in another location and purchase and install a new hard drive on your PC. Then, install Windows 10 and copy your data back onto the computer. It can also mean that the Windows 10 operating system might be corrupted. So you can reinstall or refresh the Windows in that case.

Further Reading

6 Ways to Fix Slow Boot in Windows 10

20 Tips to Speed up Windows 10 Performance

1 thought on “How to Fix 100% Disk Usage in Windows 10”

  1. You mention uninstalling Adobe Flash and uninstalling Flash updates for disk access … The latest update to Flash is prompting Win 10 users to remove it altogether now since it is no longer supported past Dec, 2020. The notice in Windows Update History is just a log entry but if Adobe Flash is removed from your computer under Apps, then the updates are already gone with it so the updates don’t need to be removed separately.


Leave a Comment