KB4507435 addresses an issue in Windows 10 Obtober 2018 Update that causes BitLocker to go into recovery mode.

Release date: July 9, 2019

Version: OS Build 17134.885

Applies to: Windows 10 version 1803

KB4507435 brings security updates to many Windows components and apps, such as Windows Wireless Networking, Microsoft Scripting Engine, and Microsoft Edge.

How to get this update:

Windows Update will automatically download and install this update.

Go to Settings > Update & Security > Windows Update and select Check for updates

Get the standalone package for this update from Microsoft Update Catalog

Issues reported for this update:

Some operations may fail with the error “STATUS_BAD_IMPERSONATION_LEVEL (0xC00000A5)”.