When you try to enable BitLocker on Windows 10 1809 (OS Build 17763.253) you have probably come across the following errors:
This errors can be inconvenient but can easily be resolved. The issue is caused by the Windows Recovery Environment being disabled.
To resolve this issue launch either Command Prompt or Powershell and run the following command to enable Windows Recovery Environment.
Now you should be able to launch BitLocker and use it as normal.