Diagnostic Service Host (WdiServiceHost) Defaults in Windows 8
The Diagnostic Service Host is used by the Diagnostic Policy Service to host diagnostics that need to run in a Local Service context. If this service is stopped, any diagnostics that depend on it will no longer function.
|Display name:||Diagnostic Service Host|
|Path:||%SystemRoot%\System32\svchost.exe -k LocalService|
Diagnostic Service Host is a Win32 service. In Windows 8 it will not be started until the user starts it. When the Diagnostic Service Host is started, it runs as NT AUTHORITY\LocalService in a process of svchost.exe, sharing it with other services. If Diagnostic Service Host fails to start, the error details are added to Windows 8 error log. When the operating system startup is complete, the user is being notified that the WdiServiceHost service hasn't been started.
Restore Default Startup Configuration for Diagnostic Service Host
1. Select your Windows 8 edition and update pack, and then click Download.
2. Save the Win8_WdiServiceHost_Service_Startup.cmd file to a local storage device.
3. Run the saved file as an administrator.
4. Restart the computer.
The WdiServiceHost service is using the wdi.dll file that is located in the %WinDir%\system32 folder. If the file is corrupted or deleted, you can put it back in there.