Cannot copy photo library from external usb to MacBook air

Hello, I recently moved our 350 gig photo library to an external USB HD. I would like to move it back. The MacBook air is running 11.2.2 and has 450 gig available. However once I try to copy it from the usb HD to the MacBook air I receive this error:

There are no other photolibrary files on the MacBook. I am at a total loss. Does anyone know how I can get our library back on the MacBook air? Thank you for your attention!