My external hard drive was full, so I had to transfer the files to a larger hard drive.
I copy and pasted all the files, and when I imported the files from the new hard drive, all of my Lightroom edits had disappeared.
Next thing I tried was "Exporting Catalogue" the old hard drive (with edits) to the new hard drive, to see if that would work. When that was completed, I "Imported Catalogue" and the original edits were still not transferred.
Can anyone help me figure out how to transfer the edits from one hard drive to another? Or synchronize the hard drives??
Any advice would be much appreciated.
... and when I imported the files from the new hard drive, all of my Lightroom edits had disappeared.
This was the mistake. Never re-import. NEVER NEVER NEVER.
You need to find your original catalog file, and use that. In your operating system, move the photos to the external HD (sounds like you did that already), and then open the original catalog and reconnect using these instructions: Adobe Lightroom - Find moved or missing files and folders
By the way, if the goal was to clear up space on the original drive, copy and paste doesn't work, you need to do a cut and paste.