Here's Explorer:

[![enter image description here](https://i.stack.imgur.com/BP4F2.png)](https://i.stack.imgur.com/BP4F2.png)

This is the Bitlocker manager:

[![enter image description here](https://i.stack.imgur.com/q4ESB.png)](https://i.stack.imgur.com/q4ESB.png)

They are obviously not in agreement and the drives ARE unlocked. Right click in explorer on S: or Z: shows the "Unlock drive" option. When selected it informs the drive is already unlocked. Double click on those drives has the same effect, since "Unlock Drive" is the default action (this is the part that bothers me).

Lastly, `manage-bde -status` is identical for S:, X: and Z: on all aspects.

Restarting explorer.exe or rebooting Windows updates explorer to the correct status of the drive. This problem happens intermittently and I have not been able to track what triggers it.

**How could I track down the cause of this problem? Maybe there is an event viewer entry related to this?**

Win 10 Pro x64 1607 (14393.351), and this issue has been happening for a while, before KB3199986 and possibly also before the other major update.