Ejecting a disc from an external hard drive
How do I force eject a disc from an Apple external drive on my iMac?
Right click or Control click on the disk you want to eject and select Eject "Disk Name". In the Finder you can also click on the eject symbol, or you can drag the disk to the Trash. Usually if it needs to be force ejected, you will get a popup window offering you the force eject option.