Exporting Photos - Partial Image
I'm working on backing up my photos to external hard drives. I keep getting random photos that only partially export. 1/3rd, 1/2, or the whole image exports as just white. On average one image per transfer has this problem. Something is causing it during the transfer, because it's not an error in the original file that is in Photos. If I re-transfer the image that has the error, it transfers like it's supposed to. I'm exporting to 3 separate hard drives (Airport and 2 other external drives). I transfer the same files 3 times in a row (once into each drive). Each time the error is on a different image on each drive, never consistently the same image getting an error on all 3 drives. I do the transfer by selecting the images I want then drag & drop to the external drive in the finder folder.
I'm using OS X Yosemite version 10.10.4 and Photos version 1.0.1.
I tried searching around to find posts with similar problems, but couldn't find any.
Any help would be greatly appreciated!
MacBook Air (13-inch Mid 2012), OS X Yosemite (10.10.4)