This post fromMiniToolintroduces how to fix the issue.

This issue is usually sparked by the corrupted Windows Management Instrumentation (WMI) repository.

What is Windows Defender app Guard?

How to Enable Windows Defender Application Guard? [5 Ways]

How to enable Windows Defender app Guard?

This post provides 5 ways for you.

Step 1: Typecmdin theSearchbox and chooseRun as administrator.

Step 2: To rebuild the WMI database, you should punch in the following command and press theEnterkey.

you’re able to turn on the Windows Defender service again.

Before you begin, yo back up your registry.

Take it easy and this post is helpful for you.

Here, multiple ways are introduced to you.

you might try them one by one until the issue gets fixed.