Boot Runner runs over the Login Window on macOS, so if you do not see the Boot Runner screen, it is usually related to the following issues:

  1. Auto login has been enabled. If auto login is enabled, the Mac will automatically log a user in to the desktop. To prevent this, go to Settings->Users & Groups. Unlock the pane and select Login Options. Turn Automatic Login to Off.
  2. Filevault has been enabled. When filevault is enabled, the user is authenticated in firmware and then the credentials are passed to the the login window and the user is automatically logged in. You can log out of the user desktop with Apple->Logout, and Boot Runner should appear.
  3. You currently have preferences set that prevent the Boot Runner from showing volumes. Remove the preferences by going to System Preferences->Profiles and removing the Boot Runner profile. If you don’t have any profiles, the System Preference may not show. Also remove the preference file/Library/Preferences/com.twocanoes.bootrunner.plist and then reboot.
  4. You are at the macOS boot selector screen. Boot Runner does not show at the boot selector screen. Select the macOS that Boot Runner is installed on, and it should show over the Login Window.

If you do not see all the volumes you expect, try the following:

  1. Remove the preferences by going to System Preferences->Profiles and removing the Boot Runner profile. If you don’t have any profiles, the System Preference may not show. Also remove the preference file/Library/Preferences/com.twocanoes.bootrunner.plist and then reboot.
  2. Make sure the volume stays mounted after you logout. Run the following command in Terminal:

    sudo defaults write /Library/Preferences/SystemConfiguration/autodiskmount AutomountDisksWithoutUserLogin -bool true

  3. Set the settings to show unmounted volumes.  See the section “Basic Settings” under “Hide volumes” from :http://twocanoes.com/knowledge-base/boot-runner-3-setup-guide/