I've checked every other "My new MBP won't see my flash drive" thread I can find, and none of them answer my question. I have a reasonably new (2 years or so) 4G flash drive that I'm trying to use to transfer some files to my new 15" retina MacBook Pro, but the new computer won't recognize it. It is NOT formatted for PC. My 2007 MBP reads it just fine, will write things to it and pull things off of it no problem. A PC will even recognize it enough to complain about the formatting. The ports on my new laptop are fine. Both have been used successfully with more than one other device. My external hard drive works just fine with the new computer. But it's a dinosaur. It weighs about 3 pounds and has its own power supply. It's just not practical to carry that around with me all the time. Any thoughts or suggestions? I'm willing to shell out the 6 bucks for a new flash drive, but how do I know I won't have the same problem with that one?