The problem being that I selected 2 folders of photographs at the same time to be moved in Lightroom to a new OWC Thunderblade 8TB SSD. One folder at a time moved very quickly but 2 at the same time slowed things down dramatically so I aborted the transfer of one of the folders. After that about 1/2 of the folders of the aborted folder remained to be moved, Nothing I could do would get LR to move the remaining folders into the partially moved parent folder on the new disk.
In retrospect I think I could have ultimately found a better solution. The one I used was to manually copy the remaining folders in Finder onto the new disk and then import them into LR. I always write imp files separately from the main file. Unfortunately I discovered that xmp files do not contain the History State - they do include keywords and snapshots. So ultimately on about 1,000 photos I lost the History State. In my particular case this is not a particular problem - that folder I had already processed and printed with adjustments the photos I wanted to keep. I also have the original RAW files if I need to go back and do them again.
But what confuses is me why I couldn't get LR to move folders from an existing parent folder to a partially moved parent folder on the new disk. What I did discover is that LR would allow me to move the individual photos within those folders. So a better solution would have been to manually recreate the subfolders on the new drive and then move the individual files to those folders. So is this a bug or am I being stupid.
Still this was a pretty easy transfer and for those who may be interested 600MB Tiff files from an X2D now load instantaneously and zip along.
