"Could Not Copy" all music since update to Windows Phone 3.0 on Mac

Question :-

I've recently updated my Windows Phone Connector for Mac to version 3.0. 
Since then I have not been able to copy any of my music from iTunes. After the synch I get the error "Could not copy "xxx" to the device".
This applies to any content from iTunes, music, podcasts, movies etc. 
This has also only happened since I updated to 3.0. The previous version worked fine.
Synching photos from iPhoto still works. 

Phone is LG Optimus 7
OS version is 7.10.8773.98
Mac is running OS 10.8.2

Any help on this would be appreciated.

Answer:-

This is related to sandboxing on MacOS when your music is stored in a different place than the Music folder. The solution is to choose File -> Allow Access to Folder... and then select the folder at the top of where your music is stored.  The default folder when the dialog comes up is the root folder for your Mac, if you choose it, this will also solve the problem.

By selecting a folder, you are giving the Windows Phone app permission to access files in that folder and this is necessary for it to sync the files to your phone.  Note that this could also happen with your photos from iPhoto or Aperture if they are stored outside of the Pictures folder.

You should only need to select the folder once.  The Windows Phone app will remember this location and future syncs will continue to work.