Galaxy S3 is unable to transfer files over USB: "USB device not recognized" I have Galaxy S3 with baseband version I9300XXLFB and I'm having problems when it is connected to the PC. I cannot transfer or retrieve any files or data over USB. 

When I plug it in to my PC, it tells me USB device not recognized and the S3 does not appear anywhere for me to access it. I've tried different cables and PCs and they all seemed to exhibit the same issue. How can I get this working?
You may need to use Samsung KIES (software for PC), or get your PC to recognize the 'new' "MTP" USB mode.

further background:

Ice Cream Sandwich supports USB mass storage after all, Galaxy Nexus does not

Wikipedia >> Media Transfer Protocol

Samsung >> SUPPORT >> Kies 2.0



Also see: Can I disable MTP mode and just have a regular USB connection?