Are you asking if you can  install Aria player without the library or how? 

Or how to point the computer to the external drive? 

I am asking how to install the necessary components (without the library) on the new computer so that when I point the new installation of Cubase to the existing library on the external drive, everything is authorized and ready to go.

From reading on how install Aria, go into your account and download the latest or previous version of the aria player. This will give you just the installation for Aria not the library after installing Aria just drag your registration card into it and should be fine.

Sadly, I see no way to do what Marcus was attempting -- whenever you want to change computers you must reinstall the whole 100gb library. Just installing the player won't create the necessary registry keys, so you can't even manually redirect the player to your library. This is absurd -- almost every soft synth I've ever used has the ability to relocate its library from within the program. So with the Aria player I must spend an hour doing what would take 30 seconds in any other player.

Making things worse, the sample folder name in the installation program doesn't match the actual folder(s) created, so one must guess where to direct the installer so that it will overwrite the existing files (direct it to "cfx_concert grand"). If you guess wrong, you'll need to cancel the installer about ten times, then start over...

Doug is right! Years ago I made a feature request for a simple way to relocate Garritan samples. Every one of my dozens of sample libraries allows changing location of samples in a minute. I have just spent an hour and Aria cannot find the samples even at the location it claims to be looking at! I have no problem rewriting and saving plist files becuase I have decades of experience as a Mac tech. But I would never ask a client to do such a thing! Looks like the software writer quit his job at Garritan right before putting the finale youches on the product!

(Of course, you might say "Since you've done this countless times before, your failure now could be due to..user error. Or ..old age!  So check out my video and see if I am doing something wrong. BTW I DID reboot after changing the plist files., and before making this video.)

https://www.dropbox.com/s/d71pbv4o7ndbfd9/Aria%20cant%20find%20samples%20at%20the%20location%20it%20is%20looking.mov?dl=0