To verify the startup from a bootable copy, open the System Preferences (Apple menu), Panel "Startup disk".
If the disk is displayed in the list, select it and click on restart.
If the drive is not displayed, it does not contain a bootable system.
Some additional information:
- Use a disc formatted GUID and HFS (see in the "Volumes" Panel).
- Use a drive connected by USB or Thunderbolt.
- Only use a programmed action of type "Bootable Copy", and avoid any filter (unless you are sure that the filter is not problems for booting; in uncertainty, no filter).
- If the disk was not empty (or if it contained an ancient system) empty it completely and restart the "Bootable Copy" action.
- If the copy fails, completely erase the disk, make sure it is well formatted and connected, restart the bootable copy and start it by the System Preferences.