How can I tell Migration Assistant to copy the data from my OLD Mac to an EXTERNAL HARD DRIVE on my NEW Mini Mac? The new Mini Mac doesn't have enough internal disc space for it all. I used Time Machine to copy all the data from my Old Mac to a second Ext Drive - and it's ready to go.
iMac 21.5″
You cannot.
Migration Assistant can only migrate data to the startup drive from which it is launched.
You will have to find another way to move your data from the old Mac to the external drive.
Simple drag-n-drop from the old Mac is one way to transfer those files if that Mac recognizes the ext drive. There are other options available. Carbon Copy Cloner or SuperDuper! can move the data to the destination of your choice.
+1 I also recommend using CarbonCopyCloner or SuperDuper.
Connect the external drive to the old Mac and clone the Macintosh HD to the external drive. Then connect the external drive to the new Mac mini. From that clone, you can access the old Mac's data and/or choose what to move to the new Mac mini.
As already said by @D.I Johnson, Migration Assistant cannot do that.
Just use the Finder to copy the data files from your old Mac to the external drive and then move the external drive over to your new Mac mini.
Note, if you run into any read/write file or folder permission problems using the external drive on the new Mac mini, just set the external drive to Ignore Permissions.
Additionally do not copy everything blindly as a substantial amount of what is on your old machine will be garbage including corrupt files which won't benefit your drive.
Only copy what you absolutely need and take this opportunity to spring-clean your equipment.
Migration Assistant to external drive on new Mac mini
