Working on Images off External Hard Drive in Catalog.

Hello, everyone. Hope all is well.

I'm new to capture pro. I noticed that in a session I can view my external hard drive, but in Catalog, I can't see the same hard drive.

Is there any way I can make that work?

Thank you. 

Update: In the Session view I can see system files, external HDDs, and their containing raw files. In Catalog, I can not see System Files. Adding the Folders will show the folders, but not the images. It will say "no images in collection"