Multimedia Class Scheduler - Windows 11 Service
Enables relative prioritization of work based on system-wide task priorities. This is intended mainly for multimedia applications. If this service is stopped, individual tasks resort to their default priority.
This service also exists in Windows 10, 7, 8 and Vista.
Startup Type
| Windows 11 version | Home | Pro | Education | Enterprise |
|---|---|---|---|---|
| 21H2 | Automatic | Automatic | Automatic | Automatic |
| 22H2 | Automatic | Automatic | Automatic | Automatic |
| 23H2 | Automatic | Automatic | Automatic | Automatic |
| 24H2 | Automatic | Automatic | Automatic | Automatic |
Default Properties
| Display name: | Multimedia Class Scheduler |
| Service name: | MMCSS |
| Type: | kernel |
| Path: | %WinDir%\system32\drivers\mmcss.sys |
| Error control: | normal |
Default Behavior
The Multimedia Class Scheduler service is a kernel mode driver. If Multimedia Class Scheduler fails to start, the error is logged. Windows 11 startup proceeds, but a message box is displayed informing you that the MMCSS service has failed to start.
Restore Default Startup Type for Multimedia Class Scheduler
Automated Restore
1. Select your Windows 11 edition and release, and then click on the Download button below.
2. Save the RestoreMultimediaClassSchedulerWindows11.bat file to any folder on a local drive such as SSD or a hard disk.
3. Right-click the downloaded batch file and select Properties.
4. Check the Unblock checkbox and click OK.
5. Right-click the batch file again and select Run as administrator.
6. Restart the computer to save changes.
Note. Make sure that the mmcss.sys file exists in the %WinDir%\system32\drivers folder. If this file is missing you can try to restore it from your Windows 11 installation media.