Yes, the catalog an be placed on an external disk. It can not be on a network drive though.
The original images can be on an external drive and on a network drive.
You did move the LR data folder (catalog and previews) only, right? You can not move the program folder.
I was having so many problems with opening my older Lightroom Folders, etc. (said they needed Upgrades), that I threw up my hands in horror and I deleted everything (from Lightroom and my laptop hard drive), so now I can literally start from scratch. I only have one catalog on an external hard drive that I worked with when I was taking a photography class at a local community college three years ago. The original RAW images are stored on my external hard drive, so I have the pictures. Now, it is a question of how best to organize images for photo editing. I am working with an online tutorial from an avid outdoors photographer, and he seems to have a rather streamlined approach to photo organization. I do not know what Julianne Kost would think about it, but this guys likes to keep things simple, and that's enough to keep me happy. I need to clear off the one file I have on my external hard drive so that it is clean, too and then create a special folder on the external hard drive to move things to. Thanks for listening and responding.