When Apple’s FileVault encryption is enabled, your USB keyboard, mouse and the USB audio device connecting to Thunderbolt Station may not work until you login to OSX screen.
Apple’s FileVault is used to encrypt your Mac startup disk and helps prevent unauthorized access to documents and other important data. With this design concept in mind, it utilizes the EFI pre-boot environment to handle the password and login. Thus, none of Mac OS X drivers will load until you type in password and login to OS X. That being said, if you have USB keyboard and mouse connected to a Thunderbolt dock, such as CalDigit Thunderbolt Station 2, or the audio ports on TS3 Plus, which is the USB base, you will not be able to use these devices during the user login process. If you have a laptop, you must use the internal keyboard to login. if you have a MacPro, you must connect the keyboard to built-in USB port on computer and type in the password for the login. After user login process, all the drivers will be loaded properly to support full functions of Thunderbolt dock and your keyboard, mouse connecting to the Station can function properly. This HOWEVER, will affect your default sound device on the dock or any USB audio interface connecting to the dock. It is not possible to keep the audio interface on the dock as default output/invoice device across the macOS restarts.
Two possible solutions:
1. Disable the FileVault disk encryption:
2. Use internal keyboard or built-in USB port to login.
Notes: This behavior applies to all Thunderbolt Docks and Thunderbolt Display.