Why do Fortnite's building hotkeys not work?

In Fortnite, I changed one hotkey: sprint from left-ctrl to 'r'. All of my hotkeys have been working fine until today when I could only press f1 of my building keys, only '1' and '3' of my numbers, and all of my keys; and then I had to scroll to access the other building and item choices. FYI: I just downloaded the season 4 update.
What is going on here?


Solution 1:

I figured out my problem: I needed to plug in my hard drive that fortnite's latest update was downloaded on. This also fixed my problem where I couldn't repair.