Using I Mac computer

Hi, need some help.  Recently replaced my PC with an I-Mac, one problem I have is that I plug my Sansa Clip + (8 Gb) into a USB Port but I Tunes can’t see it.

I changed the system setting to MSC on the Sansa but that didn’t help.

Any help or ideas will be gratefully received.

I use a Mac Mini to manage music on my Clip Sport. I discovered my Mac (and my Dell PC) only recognize my Clip Sport when I use the micro USB cable that came with my Clip Sport. My computers do not recognize my Clip Sport when I use various micro USB cables from $Tree, $5 Store, etc.