Fully installed KDE Plasma black screen on boot >unless< live USB is plugged in

Hey guys,

I have been using Manjaro on my private desktop for a couple of weeks now and really enjoy it, so decided to migrate my work laptop to Manjaro as well.
After fully installing Manjaro the laptop boots to a black screen. However, when I boot with the live USB attached, it starts up just fine (to the actual installed OS, not the live USB environment!).
The disk is encrypted but the same behaviour occurs when a non-encrypted disk (tested a non-encrypted install just to be sure).
My hunch would be a gpu driver issue? Had issues with Ubuntu on this exact laptop because of the gpu. The laptop has a Nvidia Quadro P1000 mobile. I have no idea why it would work fine when starting with the USB attached and not with the USB detached (and yeah, boot order is SSD > USB so it really is starting to the Manjaro installed on the SSD).
If this rings a bell for anyone, help would be appreciated :wink:

Regards,
Mike