If you are running an older version of Mac OSX then I would suggest you to use the web interface to transfer your photos. Simple start the app, and follow the instructions there to transfer using a web browser instead of the desktop client.
I hope this is helpful. Let us know if you need more help.
You can install the Mac client from here:
https://itunes.apple.com/us/app/photo...
If you are running an older version of Mac OSX then I would suggest you to use the web interface to transfer your photos. Simple start the app, and follow the instructions there to transfer using a web browser instead of the desktop client.
I hope this is helpful. Let us know if you need more help.
Best,
Enrique
Photo Transfer App