The best way to get help with an Navionics issue is with their online live chat option during their normal business hours of operation.
The only known issues with updating are with Windows XP & Vista which are no longer supported by Navionics.
Open their help page. Scroll down to live chat. They have extremely knowledgeable and competent employees that can resolve any issues you may encounter.
https://navionics.secure.force.com/kb/?l=en