Transfer of photos using iMac (Mavericks)

WD External and Portable SSD External SSD for macOS
1

I have had a WD ‘My Book  for Mac’ for over four years, connected to my iMac running OS-X 10.5.8, to back-up all my Canon photos, both RAW and JPEG.I have had no problems until I recently installed OS-X 10.9.1 (Mavericks). I have no problem transerring photos to the W.D. external hard drive. However, since loading Mavericks, any photo transfered post Mavericks cannot be read by Dx-O Optics, but can by Canon Digital Photo Professional, and Photoshop.  All photos transferred before installarion of Mavericks are still openedby Dx-O Optics. If the files are transferred back from My Book to my iMac hard drive, they can be read by Dx-O Optics, so the files are not being changed by the external hard drive. (Cameras used. Canon G10, 40D and 70D).

Any comments would be grateful

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Hello baillieswells, this appears to be a software problem instead of a hardware one, to be sure try running a Disk Utility test. If the test completes successfully, I would recommend contacting Apple support directly. Maybe some of the community users can also share some advice. 

How to test a drive for defects or problems on a Mac