No USB devices connected

[blan]

I am running Ubuntu 18.04 on both guest and host.

Yesterday I installed the required oracle VM extensions (see screenshot_1 attachment).

I then went to settings -> USB and selected USB 3.0 (xHCI) Controller. I pressed OK (see screenshot_2).

I then added my own user and the root user to vboxusers.

I then unmounted the USB external hard drive from my host OS, and was subsequently able to see it in list of USB devices, checked it, then was able to access it via the guest OS.

Today though - I am not able to access the USB external hard drive from the guest OS. I have checked through all the above steps today, and no luck.

[mpack]

USB Basics and Troubleshooting.