can you use file>open to open your files?
OOff course. Just becaused they were exported from LR does not prevent tou from doing anything with the folder
By "unable to view catalogs" do you mean you can't find them to open them? Or that you can't find what you thought you had in them?
Where your catalogs stored on the external drive?
Can you read and access files from the external drive, and view stored photos there?
What permissions do you have set on your external drive (do a Get Info)?
Does Lr open with an empty catalog?
You don't give us much info to help you solve your problem. Tell us in detail what you are trying to do and what happens.
How is that external hard drive formatted. Right click on it and select Get Info. Post the format of the drive.
Not sure what exactly you mean by "I am unable to Open folders on the external drive".