After Windows 10 wakes up, WIFI won't work

Solution 1:

This is a common problem with the WiFi adapters in recent Lenovo laptops. It's probably a driver problem, though I'm not ruling out just a lot of bad hardware. In either case, Lenovo has apparently forgotten how to do QA, because this problem has existed for over a year across multiple hardware lines. As far as I can tell, it's not OS-specific; I've seen it on Win8 and 8.1 as well.

You can try solutions like what @Divin3 recommended, but if that doesn't work the workaround is to just disable-and-re-enable the card. This used to be difficult, requiring Admin and so on, but if your OS offers "Airplane Mode" (in Win8.1, it's at the top of the WiFi connection sidebar) you can turn that on and then off again to bounce the WiFi adapter. Sorry for the lack of Win10-specific advice; none of my Win10 installs are running on bare metal on a laptop yet.

Solution 2:

I did two things: I installed an updated device driver, which made wireless intermittently become connected after waking up from sleep, and also un-ticked "Allow the computer to turn off this device to save power", in the "Power Management" tab of the wireless network adapter properties.