I've installed Windows 10, and I have Norton Internet Security at level 22.5.2.15. Norton tells me that everything is fine, and what I've read here says that it should be.
However, every 10 or 15 minutes (!), I get an alert that "Your NIS is incompatible with Windows 10, click Next to download a new version". I click Next and it tells me that it's Installing. But 10 or 15 minutes later, it happens again.
The only variation is that it sometimes complains that there is another download manager running.