I have the following setup with KEY: A win 10 desktop, an android phone, and a win 10 laptop. None of the devices have any third party anti-virus, only what's included in the OS. I've installed and setup the devices in that order (first installed on desktop, synced to phone, then synced to laptop). Desktop and phone work fine, no issues there, but almost every time I try syncing on the laptop I get the "incorrect synchronization code" error. About once in the every 30 tries I actually do get it to sync on the laptop and as soon as I lock KEY on the laptop it immediately forgets the sync and I need to re-sync again.
As it stands, KEY is currently pretty much unusable for me because after every system restart I need to go through the same pain of re-syncing on the laptop.