What specific exact action in Lightroom are you talking about when you "can't access" the drive?
What I mean to say is I can "see" the catalog on the external drive, I can load photos from there to Photoshop (1 at a time) but - my issue - Lightroom can not read the catalog when I try to switch from a MacAir hard drive catalog to an external drive catalog.
Is this a bit clearer?
No, it's not particularly clear.
First you were talking about "reading" photos, now you are talking about reading a catalog.
I still want to know what specific action in Lightroom you are talking about. Use the Lightroom name of the action. There is no action named "access" in LR, there is no action named "read" in Lightroom...
Ahh, "accessing" a LR catalog and photos therein on an external drive is my issue.
The LR command is:/File/Open Catalog or /Open Recent ... a list of Catalog names on the hard drive and external drive appears/choosing a catalog with photos on the hard drive opens it as is normal but opting for the catalog with my photos on the external drive has no result.
The sequence I describe here does not freeze LR, I can "back" up to the main commands at the top of the LR screen.
Thanks for your patience in clarifying this with me!
When you use File->Open Catalog, you should be able to select any file on any drive ... the dialog box that appears is your standard operating system window to select a file, is it not?
What happens when you select the catalog file on the external drive? Describe.
When I select the catalog file on the external drive, LR defaults to "Get started with Lightroom mobile" with an Import dialog that in the centre of the screen has the message "No photos inselected Collecion Set".
Hmmm ... I can only think of a very basic question here ... when you do this, are you sure you are select a LR Catalog file, whose name ends with .LRCAT (might be lower case)?