COM+ System Application (COMSysApp) Service Defaults in Windows XP

Manages the configuration and tracking of Component Object Model (COM)+-based components. If the service is stopped, most COM+-based components will not function properly. If this service is disabled, any services that explicitly depend on it will fail to start.

Default Settings

Startup type: Manual
Display name:COM+ System Application
Service name:COMSysApp
Service type:own
Error control:normal
Path:%SystemRoot%\system32\dllhost.exe /Processid:{02D4B3F1-FD88-11D1-960D-00805FC79235}
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\COMSysApp

Default Behavior

COM+ System Application is a Win32 service. In Windows XP it won't start until the current user starts it. When the COM+ System Application service is started, it is running as LocalSystem in its own process of dllhost.exe. If the COM+ System Application fails to start, the technical information about the error is added to the Event Log. Windows XP startup should proceed, but a message box should be displayed informing the user that the COMSysApp service has failed to start.


COM+ System Application depends on the Remote Procedure Call (RPC) service.

Restore Default Startup Configuration of COM+ System Application

Before you begin doing this, make sure that all the services on which COM+ System Application depends are configured by default and function properly. See the list of dependencies above.

1. Run the Command Prompt.

2. Copy the command below, paste it into the command window and press ENTER:

sc config COMSysApp start= demand

3. Close the command window and restart the computer.

The COMSysApp service is using the dllhost.exe file that is located in the C:\Windows\system32 directory. If the file is removed or corrupted, read this article to restore its original version from Windows XP installation media.