I am trying to move my photo folders from Pictures on an iMac running Mavericks to an external HD as my main photo storage and to do so with LR 5.6 keeping track of the folders. I have 20K plus photos in the Catalog in the iMac's HD and wouldn't want LR to loose track of the photos. I am not creating duplicates but moving all the files w/original photos and edits.
Is there a good and safe method to use LR to perform this task?
In your operating system, move the photos to the external HD, keeping the folder structure unchanged, and then in Lightroom reconnect using these instructions: Adobe Lightroom - Find moved or missing files and folders