How to disable or optimize SysMain to speed up Windows 11

To disable SysMain in Windows 11, open Services, set the SysMain service's Startup type to Disabled, then select Stop and OK.

This guide shows how to confirm SysMain is really the cause first, how to turn it off from Services, PowerShell or Command Prompt, how to optimize it without disabling it, and how to turn it back on.

How to disable SysMain using Services

The Services console is the quickest route and works the same way on Windows 11 and Windows 10. Sign in with an administrator account first, because a standard account cannot change a system service.

1. Press Windows + R to open the Run box.
2. Type services.msc and press Enter.
3. Scroll to SysMain (older builds list it as Superfetch), right-click it and select Properties.
4. Write down the current Startup type so you can restore it later.
5. Open the Startup type list and select Disabled.
6. Select Apply, then select Stop under Service status.
7. Select OK and close the Services console.

Disabled means the service cannot be started by you, an app or Windows until you change the startup type again. The change survives a restart, which is what makes it permanent.

What SysMain does in Windows 11

SysMain is the current service name for the feature Windows used to call Superfetch. Its job is to keep the data your PC reads most often ready in memory, so it does not have to come off the disk every time.

Detail	What Microsoft documents
Service name	SysMain
Older display name	Superfetch
Service description	Maintains and improves system performance over time
What it prepares	Data that is frequently read at startup, stored in the hibernation file (Fast Startup and hibernate) or in RAM (standby)
Why	To avoid heavy disk reads when the PC starts or resumes
What drives its workload	How much data your startup apps, services and sign-in components read
Microsoft's recommendation on disabling it	No guidance; it is not listed as required, and Microsoft disables it on its own soft real-time device builds

When SysMain can slow down your PC

SysMain does its reading in the background, so on most PCs you never notice it. It becomes visible when that background reading competes with what you are doing.

Situation	What you see	Why SysMain is involved
Right after sign-in or a restart	Disk activity stays high for a few minutes	It reads startup data into memory while your apps are also loading
A slow hard disk (HDD)	Apps stall while the disk light stays on	Its reads queue behind your own reads on a drive with little spare speed
Many startup apps	Long busy period after every boot	More startup data means more for SysMain to prepare
Low free RAM	Frequent pauses when switching apps	Cached data has less room and is dropped and re-read more often
Low free disk space	General sluggishness alongside SysMain activity	Windows has less room for paging and temporary files

If none of these match, SysMain is rarely the reason a PC feels slow, and turning it off will not change much.

How to check whether SysMain is causing performance issues

Check this before you change anything. SysMain runs inside a shared Service Host process, so you need to match the process to the service.

1. Press Ctrl + Shift + Esc to open Task Manager while the PC feels slow.
2. On the Processes tab, select the Disk column header, then the CPU column header, so the busiest processes sort to the top.
3. Expand any entry named Service Host: SysMain and note its disk and CPU figures.
4. Select Start, type resmon and select Resource Monitor for a second view; on the CPU tab, sort by Average CPU.
5. Open Command Prompt and run tasklist /svc to see which svchost.exe process ID hosts SysMain.
6. Restart the PC, wait until the desktop settles, and compare the same figures; activity that fades after a few minutes is normal startup work.

Disable SysMain only when it stays at the top of the Disk or CPU column well after startup. If another process leads, fix that process instead.

SysMain enable or disable: which setting fits your PC

Your situation	What to do	Why
SysMain stays at the top of Task Manager long after startup	Disable it	It is the measured cause, and Windows runs without it
Activity only appears for a few minutes after boot	Keep it enabled	That is the startup data being prepared, and it ends on its own
You want it off for testing only	Set it to Manual or stop it once	Easy to compare before and after without a permanent change
Older PC with a hard disk and many startup apps	Trim startup apps first, then decide	Less startup data means less SysMain work
You prefer the command line or manage several PCs	Use PowerShell or Command Prompt	One line sets the startup type and stops the service
Nothing in Task Manager points to SysMain	Leave it alone	Disabling it will not speed up the PC

How to disable SysMain using PowerShell or Command Prompt

Both shells need to run as administrator. Select Start, type PowerShell or Command Prompt, right-click the result, select Run as administrator and accept the User Account Control prompt.

1. PowerShell: run Set-Service -Name SysMain -StartupType Disabled to stop it starting again.
2. PowerShell: run Set-Service -Name SysMain -Status Stopped to stop the running service now.
3. PowerShell: run Get-Service SysMain | Select-Object -Property Name, StartType, Status and confirm Disabled and Stopped.
4. Command Prompt: run sc stop SysMain to stop the running service.
5. Command Prompt: run sc config SysMain start= disabled to block it from starting again; keep the space after start=.
6. Command Prompt: run sc query SysMain and confirm the STATE line reads STOPPED.

Without administrator rights, both shells refuse the change with an access error. sc config fails if the space after start= is missing.

Check that SysMain is disabled in Windows 11

1. Restart the PC.
2. Press Windows + R, type services.msc and press Enter.
3. Find SysMain: the Status column should be empty and Startup Type should read Disabled.
4. Press Ctrl + Shift + Esc and confirm no Service Host: SysMain entry appears on the Processes tab.
5. Use the PC normally for a day and compare disk and CPU activity with the figures you noted before.

If the PC is no faster after a day, SysMain was not the bottleneck. Turn it back on and work through the optimization table below.

How to turn SysMain back on in Windows 11

Restore the startup type you wrote down before the change. If you did not note it, Automatic lets Windows start the service at every boot.

1. Press Windows + R, type services.msc and press Enter.
2. Right-click SysMain and select Properties.
3. Set Startup type to the value you noted, or Automatic.
4. Select Apply, then select Start.
5. Select OK.
6. From an admin PowerShell window instead, run Set-Service -Name SysMain -StartupType Automatic and then Set-Service -Name SysMain -Status Running.
7. From an admin Command Prompt, run sc config SysMain start= auto and then sc start SysMain.

Ways to optimize SysMain without disabling it

SysMain's workload grows with what your PC loads at startup and shrinks when the system has spare memory and disk. Reduce that load and SysMain gets quieter while it keeps doing its job.

Change	Where to do it	Effect on SysMain
Reduce startup load	Task Manager > Startup apps, right-click an app > Disable	Less startup data to read and prepare
Stop apps running in the background	Settings > Apps > Installed apps > More options (…) > Advanced options > Let this app run in the background > Never	Frees RAM so cached data is not dropped and re-read
Free up disk space	Settings > System > Storage > Storage Sense > Run Storage Sense now, or Temporary files > Remove files	Leaves room for paging and temporary files
Check the drive and optimize it	Select Start, type Defragment and Optimize Drives, select the drive > Optimize	A well-maintained drive answers SysMain's reads faster
Let Windows finish background maintenance	Settings > Windows Update > Check for updates, install, then restart	Post-update activity settles instead of overlapping with SysMain
Use a manual startup type as a compromise	Services > SysMain > Properties > Startup type > Manual	Windows or an app can still start it on demand, but it does not start at every boot
Use a delayed start as a compromise	Services > SysMain > Properties > Startup type > Automatic (Delayed Start)	Starts shortly after the other automatic services, so boot is less crowded

On older hardware these steps help less. A move from a hard disk to a solid-state drive, or more RAM, usually does more than any service setting.

When you should keep SysMain enabled

Situation	Why SysMain is worth keeping
Task Manager does not show SysMain near the top	Disabling it removes a feature without fixing anything
You use Fast Startup, sleep or hibernate a lot	SysMain prepares the startup data those features resume from
The busy period ends a few minutes after boot	That work is what makes later app launches quicker
The PC has plenty of RAM and a fast drive	SysMain's reads finish quickly and do not compete with you
A work or school PC managed by IT	Service settings may be enforced by policy; ask the administrator first

SysMain still running or PC still slow after disabling it

SysMain starts again after a restart

The service was stopped but its startup type was left at Automatic or Manual.

1. Open Services and double-click SysMain.
2. Set Startup type to Disabled and select Apply.
3. Select Stop, then OK.
4. Restart and check the Startup Type column again.

The command fails or says access is denied

The shell is not elevated, or the space after start= is missing.

1. Close the window, select Start, type Command Prompt, right-click it and select Run as administrator.
2. Accept the User Account Control prompt.
3. Type the command again exactly as sc config SysMain start= disabled.
4. Run sc query SysMain to confirm the change.

Disabling SysMain did not improve performance

Another process or a hardware limit is the real bottleneck.

1. Open Task Manager and sort the Processes tab by Disk and then CPU.
2. Disable unneeded entries under Startup apps.
3. Run Storage Sense and Optimize the system drive.
4. Run a Quick scan from Windows Security > Virus & threat protection.
5. Turn SysMain back on if nothing changed, because it was not the cause.

SysMain in Windows 11: frequently asked questions

Is it safe to disable SysMain in Windows 11?

Yes. Windows keeps running without SysMain, and Microsoft disables it on its own soft real-time device builds. The trade-off is that Windows no longer prepares frequently used startup data, so some app launches and resumes can take a little longer.

Should I disable SysMain in Windows 11?

Only if Task Manager shows Service Host: SysMain at the top of the Disk or CPU column well after startup. If its activity ends a few minutes after boot, or another process leads the list, leave SysMain enabled and fix the real cause.

Does disabling SysMain improve performance?

It helps only when SysMain is the measured bottleneck, usually on a hard disk that stays busy after startup. On a PC where SysMain is quiet, disabling it changes nothing you will notice and removes the startup preparation it does.

What will happen if I disable SysMain?

The SysMain service stops and cannot start again until you change its startup type. Windows, your apps and your files work as before. Windows no longer pre-reads frequently used startup data into memory or the hibernation file.

Will disabling SysMain fix 100% disk usage?

Only if SysMain is the process holding the disk at 100%. Sort the Task Manager Processes tab by the Disk column first. If Service Host: SysMain is not at the top, disabling it will not lower disk usage.

Should I disable SysMain if my PC has an SSD?

Not by default. A solid-state drive answers SysMain's reads quickly, so the service rarely competes with you. Apply the same test as on any PC: disable it only if Task Manager shows SysMain using the disk or CPU long after startup.

How do I stop SysMain permanently?

Set its startup type to Disabled, not just stop it. In Services, open SysMain's Properties, choose Disabled under Startup type, select Apply and Stop. Or run sc config SysMain start= disabled from an admin Command Prompt.

How do I know if SysMain is slowing down my computer?

Open Task Manager with Ctrl + Shift + Esc and sort the Processes tab by Disk and CPU. If Service Host: SysMain stays near the top for more than a few minutes after startup, it is slowing the PC.

How do I turn off SysMain in Windows 10?

The steps match Windows 11. Press Windows + R, type services.msc, open SysMain's Properties, set Startup type to Disabled, select Apply, then Stop and OK. The PowerShell and sc commands are identical on Windows 10.

Can I optimize SysMain without fully disabling it?

Yes. Disable unneeded startup apps, free disk space with Storage Sense, optimize the drive, and set SysMain's startup type to Manual or Automatic (Delayed Start). Each change reduces how much SysMain competes with your work at boot.

Bottom line: should you disable SysMain in Windows 11?

Measure first: disable SysMain only when Task Manager shows it holding the disk or CPU long after startup, and otherwise trim startup apps and keep it on. SysMain exists to make startup and app launches faster, and turning it off is a fix only when it is the measured bottleneck. The change takes one minute to undo from Services if the PC is no faster.