You can not play or access AVCHD videos from camcorder connected via USB as an external storage device, or from removable media or from your computer’s internal hard drive.
The reason, I know its hard to believe I know, but the default media players QuickTime don’t have an AVCHD Player built in.
But it is easy to solve the problem! This is how to play and access AVCHD video on Mac using VLC media player.
1. Download VLC Media Player and install it on your computer.
2. Click on the ”Media” then ”Open” from the top navigation menu on the player. Lead the movie file in the player to open. Click ”OK” to open the file.
If you just want to watch the film start to play.
3 If you want to access the files i Finder and save the on your Mac for editing for example in Premiere. Right clic on one file and choose View in Finder.