When installing the OS, the same problem ocurred. I was plugging the USB drive to a front USB 3.0 port in my case. When I changed the USB drive to a USB 2.0 port in the back everything continued normally.
So, I'm thinking that there's a problem with USB? I installed Mojave into a M.2 SSD. Any help would be appreciated.
CPU: Ryzen 7 2700x
Motherboard: MSI B450i Gaming Plus AC
RAM: 32 GB Corsair Vengeance 3200 MHz
GPU: Sapphire Pulse Radeon RX 570 4 GB