After a big office revamp, I tried plugging my Linksys 8 port gigabit switch into my router, and then plugging one computer into the switch.
I got one of those "limited connection" messages which amounts to the same thing as no connection at all. After googling, I see there are some sophisticated reasons and sophisticated remedies, all of which are over my head.
I figured maybe my switch was bad. That's something I can understand. But before buying a new switch, I tried a different ethernet cable.
Bang. My switch works after all. The ethernet cable was bad.
Unfortunately, all that googling had never landed me on such an answer. And it wasn't intuitive, at least not to me, that a bad cable could throw such a message. But apparently it can.
So there you go. Now it's someplace on the web. If you're getting that limited connection message and you're using a switch, try swapping out each ethernet cable before going and buying a new switch.
Malwarebytes Antimalware free has a setting under "general settings" to turn on the context menu. Make sure that's on. Once done, you can close Mbam and then right click next to the folder you want to scan, and select Mbam.