Metadata missing

Thank you for getting back to me. I am using Lightroom Classic. Here’s a little history of how I got to where I am. This last fall, I upgraded my intel-based iMac to the new M3 iMac. At the time, I was backing up to a mechanical hard drive. Before recently migrating to the new computer, I consulted with a specialist and moved my files to an SDS drive. I also implemented Apple’s Time Machine. The idea was to have the older system ready to transfer the files onto the new iMac (which I recently did). All Apple-based applications and data transferred nicely, but non-Apple applications required new installations. All my Endnote and Word documents are fine. But not Lightroom. The Keword library is intact, but the corresponding metadata for each photo is largely lacking. You seem to suggest that copying, at some level, is what went wrong. If so, perhaps I could go back to the data on the original mechanical hard drive and start over.