Android File Transfer not working?
First I would suggest checking if there are any updates available, both for your MAC and Android File Transfer.

Next, something you can try is clearing the cached data for the storage on your device.

This has worked in the past for other users who have had similar issues with empty folders in the past. It's a fairly short and simple procedure that can't hurt to try. You can do that with the following steps:


Go to phone Settings
Select Application Manager
Tap on the 3 dots
Select 'Show System Apps'
Search for 'External Storage and Media Storage' 
Clear Cache and Data
Reboot the phone


This will rebuild the database without deleting any of your data. It may take a while for everything the be initialized again. 

Let me know if this helps! 

Source(s):
http://androidforums.com/threads/android-file-transfer-on-mac-showing-empty-folders-on-phone.638113/ Last post

https://productforums.google.com/forum/#!topic/nexus/UqQZmSd7hAg Best answer