Why Can't I Turn Off BitLocker in Windows® 10?

In BitLocker Drive Encryption menu, there is only Backup your recovery key option, no Turn off BitLocker option.

This issue is caused by Windows account permissions limitation, login to the administrator account to disable BitLocker:

1. Right-click Windows Start button (or Press the Windows Key + x)
2. Click Computer Management
3. Double click Local Users and Groups
4. Double click Users
5. Double click Administrator
6. Disable Account is disabled, click OK
7. Click Windows Start button
8. Click avatar (the circle image for the account currently signed in)
9. Select Administrator Account to login
10. Press Windows Start button
11. Type bitlocker
12. Click Manage BitLocker to enter the BitLocker Drive Encryption menu
13. Select Turn off BitLocker to proceed with decryption
14. Switch back to the user account