I am using LR6 with a 500 gb MBP.
I want to make sure that I have my LR catalog and its corresponding original files on an external drive. All help greatly appreciated.
You move the catalog file and photos using your operating system to the new hard drive.
You keep the folder hierarchy and structure EXACTLY the same on the new hard drive. Do NOT take this as an opportunity to "clean up" the folder structure or to move things from folder to folder.
You double-click on the catalog file, and then reconnect the photos in Lightroom using these instructions: Adobe Lightroom - Find moved or missing files and folders (see Figure 4)
Thank you very much.