I am running 2 versions of Lightroom version 3.5 on a mac desktop and version 6.3 on a mac laptop . the problem i am incurring is on the import module on version 6.3 on a laptop images are not showing up in the grid view to preview before importing .
I have cross checked preferences , the laptop is not highlighting the MOVE or ADD function . very frustrating . the desktop version works perfectly
I suppose you have a very good reason to run 2 different versions of LR? I would install the latest version on both computers.