This AM, after spending a few days doing some development on a driver - I needed to reboot my hub.
After the reboot - I clicked on 'Apps' and all I got was a spinning loading screen.
I rebooted the hub again via the :8081 page.
after the reboot, all was the same - Except I noticed more problems that I didn't notice first. When I opened the devices page, it would not scroll down.
The app page and settings pages both just sat and spun.
Not panicking - I went into my browser and looked at the cache content. I cleared the browser and rebooted the hub again from the :8081.
Everything worked correctly.
I post this for users who are scratching their heads about their hubs and can't get pages to load - maybe the cache is corrupted...