Diagnostic System Host (WdiSystemHost) Service Defaults in Windows 10

The Diagnostic System Host is used by the Diagnostic Policy Service to host diagnostics that need to run in a Local System context. If this service is stopped, any diagnostics that depend on it will no longer function.

Default Settings

Startup type:Manual
Display name:Diagnostic System Host
Service name:WdiSystemHost
Service type:share
Error control:normal
Object:LocalSystem
Path:%SystemRoot%\System32\svchost.exe -k LocalSystemNetworkRestricted -p
File:%SystemRoot%\system32\wdi.dll
Registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WdiSystemHost
Privileges:
  • SeChangeNotifyPrivilege
  • SeImpersonatePrivilege
  • SeTcbPrivilege
  • SeDebugPrivilege
  • SeAssignPrimaryTokenPrivilege
  • SeIncreaseQuotaPrivilege
  • SeProfileSingleProcessPrivilege
  • SeSystemEnvironmentPrivilege

Default Behavior

Diagnostic System Host is a Win32 service. In Windows 10 it is starting only if the user, an application or another service starts it. When the Diagnostic System Host service is started, it is running as LocalSystem in a shared process of svchost.exe along with other services. If Diagnostic System Host fails to start, the failure details are being recorded into Event Log. Then Windows 10 will start up and notify the user that the WdiSystemHost service has failed to start due to the error.

Restore Default Startup Configuration for Diagnostic System Host

1. Run the Command Prompt as an administrator.

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

sc config WdiSystemHost start= demand

3. Close the command window and restart the computer.

The WdiSystemHost service is using the wdi.dll file that is located in the %WinDir%\system32 folder. If the file is changed, damaged or deleted, you can restore its original version from Windows 10 installation media.