1. The destination location seems to have plenty of space to accommodate the transfer. (e.g. about 280 GB of free space) 2. I could find no evidence of damage to the jpgs. All applicaitons seem to be able to read and process them. I have even taken the extra step, using Lightroom, to save duplicate files in a sub-directory, but even the duplicates fail to sync. 3. After starting the sync, I do not make any changes to the files. I cannot say with absolute certainty that there is not a process running in the background that might be making changes to these files (for whatever crazy and un