Error: "Some system software requires your attention before it can be used" after installing Microsoft Defender for Endpoint on your Mac


Symptoms

After installing Microsoft Defender for Endpoint on your Mac, you notice the following message in System Preferences > Security & Privacy:

Some system software requires your attention before it can be used.

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Cause

Apple requires that all new system extensions being installed from third-party developers in macOS be manually allowed.

Resolution

1) In the bottom left-hand corner, click the lock icon.

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2) Authenticate using Touch ID or the username and password of an administrator on your Mac.

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3) Click Details.

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4) Check the box(es) next to "Microsoft Defender ATP.app". Then, click OK.

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5) Close System Preferences.

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OUTCOME

The message in System Preferences will be gone and Microsoft Defender for Endpoint will function as expected on your Mac.