There are few reports of users having Bitlocker issues following the October 2016 patches.

The issue: On every reboot, the Bitlocker recovery key is required which is quite disruptive and cumbersome. As a workaround in order to solve this issue, the following steps can be taken:

On the next reboot and once in Windows, reset Bitlocker by disabling and re-enabling it.
In administraive command prompt, do the following:
manage-bde -protectors c:-disable
then do this:
manage-bde -protectors c:-enable

At this time, I’m not certain on which patch is causing the issue but I wanted to share this info to help. You can also discuss in this TechNet post.

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