Multimedia Class Scheduler - Windows 10 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 11, 8 and Vista.
Startup Type
| Windows 10 version | Home | Pro | Education | Enterprise |
|---|---|---|---|---|
| 1507 | Automatic | Automatic | Automatic | Automatic |
| 1511 | Automatic | Automatic | Automatic | Automatic |
| 1607 | Automatic | Automatic | Automatic | Automatic |
| 1703 | Automatic | Automatic | Automatic | Automatic |
| 1709 | Automatic | Automatic | Automatic | Automatic |
| 1803 | Automatic | Automatic | Automatic | Automatic |
| 1809 | Automatic | Automatic | Automatic | Automatic |
| 1903 | Automatic | Automatic | Automatic | Automatic |
| 1909 | Automatic | Automatic | Automatic | Automatic |
| 2004 | Automatic | Automatic | Automatic | Automatic |
| 20H2 | Automatic | Automatic | Automatic | Automatic |
| 21H1 | Automatic | Automatic | Automatic | Automatic |
| 21H2 | Automatic | Automatic | Automatic | Automatic |
| 22H2 | 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 10 startup proceeds, but a message box is displayed informing you that the MMCSS service has failed to start.
Restore Default Startup Type of Multimedia Class Scheduler
Automated Restore
1. Select your Windows 10 edition and release, and then click on the Download button below.
2. Save the RestoreMultimediaClassSchedulerWindows10.bat file to any folder on your hard drive.
3. Right-click the downloaded batch file and select Run as administrator.
4. 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 10 installation media.