Lightroom edits disappeared after backing up to an external hard drive
I don't profess to know a lot about Lightroom so go easy on me.
Recently I backed up my images to my external hard drive because my computer was running out of disk space. Once the images were backed up to the hard drive I deleted them off my internal hard drive. Now I am trying to access some of my files on my external hard drice that I had previously edited and all of the edits are gone. I left the files in the NEF format, I did not export them to tif or jpeg as I normally did.
What did I do wrong? Did I need to export all the NEF files into a jpeg or tif format? What can I do to avoid this happening again? And can I get the edits back?
I am working with Lightroom Classic version 8.3.1
