Windows 10 Update Disables Microsoft Defender

Update Disables Microsoft Defender
Written by Valdis Koks

The cumulative update KB4520062 for Windows 10 (version 1809) disables the Microsoft Defender security solution pre-installed on the system.

KB4520062, an additional non-security update, was released on October 15 and is intended to resolve a problem that may cause black screens to appear during startup during the first login after installing the previous update.

KB4520062 also addresses an issue affecting Bluetooth when using certain audio profiles for extended periods and one known to cause high power consumption for devices in Connected Standby mode.

According to Microsoft, after installing update KB4520062, Microsoft Defender Advanced Threat Protection (ATP) stops working on some devices.

“Microsoft Defender Advanced Threat Protection may stop reporting and reporting.” You can also see error 0xc0000409 in Event Viewer in MsSense.exe”, – Microsoft said.

In addition to Windows 10 (version 1809), the problem also affects Windows 10 Enterprise LTSC 2019, Windows Server (version 1809), and Windows Server 2019. Currently, for users that have lost Microsoft ATP after installing the update, there is no other solution to the problem except removing the problem patch.

“At this time, we suggest that devices in an affected environment do not install KB4520062. We are working on a resolution and estimate a solution will be available in mid-November,” — says Microsoft.

Of course, in this case, new added by Microsoft features will disappear, but the antivirus will work again and the attack surface of the devices will not increase.

Read also: Microsoft continues to release problematic Windows 10 updates one after other

Microsoft is working on a fix, which is most likely to be released along with other patches as part of the planned “Tuesday Updates” November 12th.

How to remove update?

The step by step procedure needed to uninstall this update requires opening Control Panel, go to Programs > Programs and Features, and click on View installed updates in the left sidebar.

Next, right-click on the KB4520062 entry in the list and confirm when asked if “Are you sure you want to uninstall this update?”.

Next, you’ll have to click ‘Yes’ when asked and then restart your device.

About the author

Valdis Koks

Security engineer, reverse engineering and memory forensics

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