The Sync issue has been caused by an update to Apple software released on Friday 20th May 2016.
This issue is out of our hands or our control however our technical team has worked tirelessly to ensure a solution was found.
Attached is a freshly released Sync App which has been thoroughly tested, however, please feedback any issues you may experience.
You will need to first remove the existing Sync App from your Mac and then install the new App before attempting to Sync.
STEP 1. UN-INSTALL SYNC APP
First click the Apple icon on the top left of your screen. A menu will appear.
Choose "Force Quit..."
A pop up window will appear with all running applications in it. Choose "GPS Log Book Sync App" and the click the "Force Quit" Button.
Next, go to your Applications Folder and hold-click the GPS Log Book Sync App programme and drag it across your screen to the Trash in the bottom right corner of your screen in the task bar pop-up and release it.
STEP 2. INSTALL THE SYNC APP
Click on the attached file to download it, and once downloaded use Finder to view your Downloads folder.
In your downloads folder you will see an installer file titled "GPSLogBookSyncinstaller.NZ.Mac.1.6.pkg"
Double click this file and follow the instructions in the installation wizard to complete the install.
If you are advised that your security settings are preventing you from installing the SyncApp please open your System preferences and click "Security & Privacy as shown below:
On the General tab, select "Anywhere" as an option to install applications as shown below. You may be prompted at this point to allow the installation of the SyncApp, in which case you should allow it to install, meaning you will not need to alter the setting below.
Thereafter you will be able to install the SyncApp, or if you were prompted to allow the install you will be able to sync your device normally.
Thanks for all your efforts to get this done!