I now have 2 new WD drives (4 TByte the other a 2 TByte) that do not mount on my iMac running OS 10.7.5. The Apple Disc Utility does not see them either.
However they do mount on my Macbook Pro with OS 10.9.5.
I have several projects on my iMac and do not want to upgrade OSX.
Is there a way to use these drives?