(solved)VM will not boot when virtual hard drive is attached to it

I am trying to access my sd card from a guest OS in a virtual machine using VirtualBox. I have followed some instructions on how to attach a virtual hard drive to the VM (https://superuser.com/questions/373463/how-to-access-an-sd-card-from-a-virtual-machine/458085), but when I boot the guest OS, It won't boot and instead this message appears:

"FATAL: No bootable medium found! System halted."

When I exit the VM, go to the settings of the VM and detach the virtual hard drive, and boot it again, the guest OS boots perfectly normal.

I found my own, super stupid solution:

I went into my VMs settings > storage, and instead of selecting the virtual hard drive at the right of "Controller IDE", I detached it and attached it at the right of "Controller SATA", have no idea how this worked lol!