I received my new Home Hub 6 and connected Windows 10 Laptop, iPhones, iPads, Fire TV Sticks and Consoles without any problems, but my old Windows 7 desktop refused to connect, no matter what I did.
The solution was to access the router via my phone's safari browser using the IP address 192.168.1.254 and admin password.
Go into the wifi settings and change the 'seperate bands' setting from 'off' to 'on' for 5ghz and 2.4ghz.
Change the 2.4ghz channel from '1 (smart)' to 'channel 6'.
Save the settings then change the the 'seperate bands' setting from 'on' to 'off' and save once more.
The desktop then saw one network and connected to it with no problems.
Hope this helps someone!
That's a standard fix for wifi problems with hh6 and is posted many times on the forum. Normally you would leave the 2.4/5ghz networks split not join them again. I would normally suggest to select channels annually by turning auto select off
posting solution again can't do any harm