video files from sd card not opening

I'm a rather newbie to the Yuneec Q500 4K and editing in 4K. I have premiere pro CS5 on a mac and edit in it frequently using 1080P files. I imported a flight of about 13 minutes today and found it broken into 3 files. The first files 2 were 5 minutes in length (found out that is normal!)...

I had a problem getting my files from the micro sd card on my 4k cgo3 to open. It did not matter if the photos or videos were made while on the copter or on the hand held device. some of the files would open and some would not. transferring them to my hard drive did not seem to help. after a lot...