Pc Guide

Fix if the Sysmain process is using too much disk

Disk at 100%

If your PC slows down noticeably while we open programs, when opening a new browser tab or while copying files, you need to Quickly check the percentage of disk used by Windows to see if it’s because of the SysMain service in Windows (formerly known as SuperFetch or Prefetch).

If the disk usage by this process is 100% or similar (98% or 99%) the entire operating system will slow down, regardless of the nature of the disk (even SSDs slow down if they are overloaded!). With such a loaded disk it will not be possible to maintain the level of productivity maintained up to that moment.

In the following guide we will show you how to fix high disk usage for SysMain service in Windowsinvestigating why this process causes the slowdown and how to disable it on Windows 11 e su Windows 10.

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1) What is SysMain (Superfetch)?

Superfetch, called SysMain after a particular Windows 10 update, is a feature designed by Microsoft to improve system performance over time. It studies RAM usage patterns, identifies the programs we run most often on your PC, and preloads them so they run faster.

In order to perform this optimization Superfetch needs resources, especially the system disk. This process is recognizable by opening Activity management on Windows, where it is present as Service Host: SysMain.

If this process takes up too many disk resources, we can disable it using one of the methods in the following chapters.

2) Deactivate SysMain from Services

The best way to stop SysMain is from the Windows Services tool, where it is present as a system service in the autostart car. To disable SysMain and from the Windows Services tool press the WIN+R keys on the keyboard, type services.msc and scroll through the list until we find the process SysMain.

After identifying the service we right click on it, press on Property and, in the new window, press on the button Interrupt and we set Disabled in the drop-down menu Startup type. For the changes to take effect, restart the system.

3) Disable SysMain from the command prompt

Another very quick method to solve the high disk usage for the SysMain service in Windows is to use the Command Prompt. To proceed, press on the Start menu, look for the application Command Promptright-click on it, select Run as administrator and run the following command:

sc stop "SysMain" & sc config "SysMain" start=disabled

This command will immediately stop the SysMain process and prevent it from running automatically on subsequent Windows starts, facilitating the procedure seen just now by the Services tool.

4) Disable SysMain from the system registry

An alternative method of disabling SysMain involves editing the Windows registry. If interested in this method, all we have to do is press WIN+R on the keyboard, type regedit in the field that will appear and, once the Registry Editor is open, take us to the following path:


Once the folder is opened, we identify the key Start in the right screen, we double click on it and set 4 as the key value. At the end of the modification, restart the PC to make the deactivation of SysMain effective.

5) Reset SysMain with SFC

If the SysMain feature has worked well so far and we don’t want to disable it completely at the first hint of problems, we can try to restore correct functioning by running the SFC command, which can repair damaged or corrupted system processes.

To do this, open the Start menu, type Command Promptright-click on the menu item of the same name, press on Run as administrator and, in the new window that will appear, type the following command:

sfc /scannow

This will start the search for damaged and corrupted system files, which will be promptly replaced (using the installation base already present on Windows).

To repair damaged system files we can also read our guides on how to fix corrupted system files on windows 11 and 10 come on how to use the DISM Interface to clean and repair Windows.


SysMain allows you to optimize computer performance, speeding up the startup of the most used applications. On PCs with a few years behind this function it may take up too much system resources, hence making your PC run slower. In this case, just follow one of the recommendations shown above to disable or repair it, thus freeing up resources for the applications.

Still on the subject of slow disk on Windows we can read our guides on how to solve if Windows uses the disk too much and the PC slows down and on quick tricks to make your computer faster.

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