Android File Transfer Problems?

[AC Question]

Ok so i got a shield k1 tablet to record some videos for youtube. I use the screen recorder AirShou from the play store. I recently looked up how to transfer the video onto my computer. I HAVE A MAC. It told me to download the android file transfer application so i did. I launched the application and it said that i need to unplug the usb and unlock the tablet because of my passcode. I did it, but the message keeps popping up! Can someone please help me?!?!?!