Are you adding images directly from the external hard drive to Lightroom CC?
Do you have the below option unchecked in Lightroom CC? Since you have all the images on the external hard drive then, you don't need another local storage. Therefore, you can uncheck the option for "Store a copy of ALL originally locally".
Thanks for the reply! This is indeed unchecked. I am not sure I grasp the whole concept right though...
Now what I did is I changed the Folder Location in the CC App from its default (my laptop HD) to the external laptop where the images reside now. I copied some of them to that folder (which still shows on the left pane in the Finder window of my Mac) and I get a message that it is synching. From the web interface I see that it is actually creating the folder structure and I am assuming that at some point it will copy everything there (on the cloud), right?
Question: Now my external drive is connected to the mac and the folder (CC Files) is in there. In order to access these files from the cloud, will it be be necessary to have the drive plugged into the Mac and have everything running?
If the import is finished from the external hard drive then you can remove the external hard drive and check if you are still able to edits the images.