Cheers hazelnut,
Yep, I've heard that one and about a hundred other solutions, none of them seem to work for more than a day or two at most.
And of course it doesn't only happen on boot or restart; the internet connection just drops out randomly.
(Which would seem to rule out the problem being Fast Start / Hybrid Boot).
It does seem to have something to do with the IP allocation from the router, why it suddenly drops out mid session is a bit of a mystery. (but see below)
Some have tried setting up with a static IP rather than letting the router allocate one each time, but even that only works for a while.
It only happens with wifi.
It's a strange problem, from looking on google it affects various makes of laptop, with various different network adaptors/cards, different routers, and different Windows versions.
(It's mainly with Win 10, but seems to have started with Win8, and I have also seen reports of it now happening on Vista and Win7 machines).
With myself it also seems to happen more at certain times of the day and not happen at all at other times.
(Less power on the grid at peak times, weaker signal from the router? I'll have to try keeping a log)
Try googling "No Internet, Secured" to see how many are having this problem.
The only thing that seems to cure it permanently is to swap out the network adaptor for one with a higher spec, or maybe its just because a different card will use a different driver?
But even that is not guaranteed to work everytime.
Like any other intermittent problem it's proving hard to track down just what is causing it, especially as it is affecting so many different setups.
The best theory that I have seen is that it's something to do with Windows Firewall or Security Settings that suddenly blocks wifi access for a moment, causing the laptop to have to reconnect to the router wifi and ask for a new IP, which for some reason it doesn't get.
That would explain why disconnecting and reconnecting again, or renewing "ipconfig", sorts it out for a while.
(Until the next time the Firewall or whatever blocks the wifi connection again).
All strange, and I would not be at all surprised if the problem suddenly dissapears after one of the many Windows 10 updates.