Recently I found that my laptop is becoming unresponsive for no reason. And when I checked the task manager it was showing almost a full disk space. But actually it is not the case. So I investigated further and found a service SysMain is taking up all the resources. Before 18H2 update its name was SuperFetch. After researching further, I found that you can disable this service safely to fix this issue. So lets know more about Superfetch or SysMain.

If your games are lagging, computer is responding extremely slow, showing high disk usage, CPU usage or memory usage then it could be due to the issue with the SysMain or Superfetch service. Sometimes it resolved automatically but at any point it again become unresponsive.

This service may also create the 100% disk issue. So disabling or fixing the issue related the Superfetch may also fix the 100% disk usage issue as well. Before going further first lets know about the Sysmain service in Windows 10.

What is SuperFetch or SysMain?

Superfetch or SysMain is a legitimate Windows 10 service. It analyze the computer usage pattern and optimize the apps launching accordingly. This helps to speed up the app launching. Though this service is to speed up the apps but some times it start creating issues to some users like high CPU usage and high disk usage. In Windows XP it was known as the Prefetch service and in Windows vista it was renamed to Superfetch. Actually both services are same. In Windows 10 After 1809 update it was renamed to SysMain but the thing is same.

So what it does and should you disable it?

Actually it learns the user’s system usage pattern and efficiently manage the system for faster loading of apps and faster boot time. It is not a required service but is just for optimal performance of the system. If you want to disable it you can do it safely. In my computer after deactivating it, I didn’t found any performance difference. But I got positive result that now it is now slowing down my system in between work. So lets see how you can disable this service.

How can I stop Service host SysMain from using all disk?

1. Stop SysMain service

Use Windows Services

SysMain high disk usage
  1. Press the Windows key + R.
  2. Type services.msc and click OK to open Services.
  3. In the Services window, locate SysMain
    SysMain high disk usage
  4. Right-click on SysMain and select Properties.
  5. Click the Stop button.
  6. Click OK to save the changes.

Open the Task Manager and check the disk usage and see if it is normal. Stopping the SysMain services from Services can help you resolve the high disk usage caused by the process.

If the issue persists, there are two more ways to stop the SysMain service.

Use the Command Prompt

SysMain high disk usage
  1. Press the Windows
  2. Type cmd.
  3. Click on Open Run as Administrator to open the Command Prompt.
  4. In the Command Prompt window, type the following command and hit enter:
    sc stop “SysMain” & sc config “SysMain” start=disabled
  5. You should see Change Service Config Success

Close the Command Prompt and open the Task Manager again to check the disk usage.

Use the Registry Editor

SysMain high disk usage
  1. Press the Windows key + R.
  2. Type regedit and click OK.
  3. In Registry Editor, navigate to the following location:
    HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SysMain
  4. You can copy-paste the above path in Registry Editor to navigate quickly.
  5. In the right pane, right-click on Start and select Modify.
    SysMain high disk usage
  6. Enter 4 in the Value Data
  7. Click OK to save the changes.

Close the Registry Editor and then launch the Task Manager from the Taskbar. Check if the high disk usage issue is resolved.


2. Check your hard drive

High Disk Usage Service Host

If your Windows computer has a traditional mechanical hard drive, consider upgrading to an SSD. Having your Windows installation and other frequently accessed programs in an SSD makes a lot of difference.

Most of the modern laptops come with an M.2 slot to install NVMe SSD. If not, you can buy a separate caddy to install the SSD on your old laptop.

We have an excellent guide to help you find the best 250GB and 500GB SSDs for your PC and laptop.

The high disk usage issue usually occurs when the essential system processes run in the background. However, having an SSD will significantly reduce the chances of getting a high disk usage issue.

How to Disable SysMain Service?

Here is a quick method to disable this service in the Windows 10.

  1. Type services in the search box on task bar.
  2. Click on the services.
  3. Double click on the SuperFetch or SysMain service. Or right click and select properties.
  4. Set the startup type ‘Disabled‘. And also click on the Stop button to stop the service immediately.
Note:

If you are unable to locate the Superfetch then look for SysMain as it was renamed in October 2018 update of Windows 10. Search for both the services and disable which ever you find.

Disable SysMain service

Though after deactivating it there should be possibility that it might reactivated again when you got new Windows updates. So we need to disable it again. Then I investigated further and tried to find out a permanent solution for this issue. And below are some steps which fix my issue without disabling it.

How to Fix Superfetch / Sysmain service issue?

Below steps can be useful to fix this issue permanently without disabling it. Because disabling a Windows inbuilt feature in not recommended.

  • Update Windows: Installing all the latest Windows updates may fix many of the Windows 10 issues.
  • Update all device drivers / software and games.
  • Run a PC optimizer to fix any registry related issue or any other configuration issue.
  • If nothing else work you can also try Resetting Windows.

My findings

I found no significant speed difference after disabling it. So there is no matter it is activated or deactivated your computer will still run smoothly without any speed impact.

Since the latest 20H2 Windows updates I am not facing any such issue, though my service is activated. So hopefully Microsoft has fixed this issue.

FAQs

If Service host SuperFetch / SysMain is useful then why it creates problem?

Is it safe to disable Sysmain?