Windows Server 2016 – “Windows Defender Service” won’t start – 0x80070003 (2147942403)

We had a Windows Server 2016 server where the “Windows Defender Service” service would not start – trying to start the service resulted in the message:

Windows could not start the Windows Defender Service service on local computer 0x80070003

The system cannot find the path specified

I found a question on the Microsoft website from someone with the same issue.

The marked answer said:

Solution for us was copy over "C:\ProgramData\Microsoft\Windows Defender\platform" from a working installation.

But you have to copy it offline, if you have a VM, mount the .vhdx File on the Host.

I looked on the server and found that the “platform” folder was indeed missing:

Since I don’t manage the VMWare platform, I figured I’d try to copy it over while it was running.  I tried copying and pasting in Windows Explorer and copying from the command line and neither worked, command line failed with “File creation error – The system cannot find the file specified.”

Here’s what did work:

On a working server, I copied the folder to my user profile:

WORKING SERVER

C:\Users\_tdurning>xcopy /hickey “C:\ProgramData\Microsoft\Windows Defender\platform” platform

Then on the broken server, I used Windows Explorer to browse to my profile on the working server and copied the folder.

BROKEN SERVER

And just because I’m paranoid, I made a copy of it.

I then dragged the folder “platform – Copy” to the “C:\ProgramData\Microsoft\Windows Defender” folder.

I was then able to rename the folder from the command line:

And start the service.