I have a new Lenovo Carbon X1 4th gen. Wired internet with an adapter works fine, but the wifi won't work. I tried installing the newest drivers, reinstalling windows, and even installing drivers for similar models. Everything has the same issue: Windows will report it's connected to wifi and has internet.
Chrome will attempt to load pages. But pages won't load - at all. They'll just keep trying to download forever and get very little data (some things will download, usually just the header).
Bizarrely, some websites are except from this. Google searches, for example, work perfectly; anything that ends in google.com works fine. I've tried leaving DNS/IP settings on automatic and using Google DNS but nothing changes.
Answer
"Google sites work, but other sites don't" is often due to what's known as a "Path MTU Discovery black hole". A PMTUD black hole is when something on your network — probably a local NAT gateway or firewall — either isn't sending ICMP "destination unreachable; fragmentation required but 'don't fragment' bit set" messages, or is blocking those messages from other network middleboxes.
To see if this is the case and work around it, try temporarily setting your MTU down to something low-ish like 1300 on your laptop's Wi-Fi interface. If all sites work when you're using a 1300-byte MTU, try adjusting it back upwards until you find the highest value that works.
Google sites are smart about this and always negotiate a TCP MSS (that's like the TCP-layer equivalent of an MTU) that results in an IP-layer MTU that's enough below 1500 to work on most networks, even if those networks have path MTU problems. That's why "Google sites work but other sites don't" is usually a give-away for this particular problem.
If manually setting a low MTU doesn't fix the problem, then your problem probably isn't a PMTUD black hole.
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