On both of your systems can you please use task manager (ctrl-alt-delete) to stop the following process: quicksync.exe, quicksyncMAPI.exe, and javaw.exe

The navigate to your user profile folder, and there will be a folder called .quicksync delete this folder on both systems. (folder may also be called: .migodesktop, or .syncables)

Then restart the software on both systems, and authorize your second system.