Two challenges with my Dell G7 15 7588 and Ubuntu 18.04
Ubuntu freezes when the (nVidia 1060 Max Q) GPU is used. Tried modifying the GRUB to not use it by adding nouveau and tried installing the driver from nvidia, it did not work yet. Hence had to revert back and use Intel's default GPU.
Whenever I plug in an external harddisk, Ubuntu freezes a minute or two after the auto mount kicks in.