I am using LR5 on a Windows 7 machine. I keep all of my photographs and catalog on an external hard drive and back everything up to another external hard drive. I recently removed the drive that I work from so that I could work on some photographs from my laptop while working remotely (I have no cloud services). I reconnected the hard drive, restarted my desktop and then launched LR5. I can see the drive as being on line, but none of the folder structure that I have created over the years is visible. Under the catalog tab I see All Photographs, Quick Collections, Previous Import, and Missing Photographs. I tried relaunching the catalog from the File menu and from the folder on the hard drive by double clicking on the lrcat file. However, I still cannot see the folder structure in LR5. I can see all of the folders in my LR photo catalog, and all of the files within those folders. When I edit any of the photos, I get prompted to go find the file, which I can do. Any idea as to what is happening?