Fresh download of Focal, verified SHA256. Boot from USB on my XPS5 test PC, all looks fine until the point where one can "Try" or "Install". Screen is tearing so badly, it is difficult to hit "Try". If successful, load continues to a desktop that is malformed, tearing and is an odd yellow and violet color. Top bar is visible, but attempting shutdown via the icon does not work. Ctrl-Alt-T accesses terminal to shutdown from there.

Ubuntu 18.04.3 works fine on this PC.

Dell XPS5, 4GB RAM. Nvidia GeForce 6800

No one else is reporting this issue from reading screen tearing posts. Solution?

Thanks, Dennis

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    There is a mention of problems with Nvidia in Focal release notes, and a suggestion to use safe graphics mode. I doubt it will help much, as there is no proprietary Nvidia driver to install. With very old hardware, the choices are limited, so you use what works, rather then the latest and greatest. Apr 25, 2020 at 11:58
  • Thanks mikewhatever. I'm hoping to find a way to include nomodeset or whatever parameter is useful onto the boot USB. The whole purpose of a test PC is to wring something out before installing it to production. There are 11 Linux machines in the lab, with all kinds of distros running on them. The XPS5 has 10 partitions with a different OS on each. Thanks again!
    – Dennis J
    Apr 25, 2020 at 12:32
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  • YES! karel, you were the one who pointed me in the right direction. I forgot that GRUB only shows up automatically on multi-boot systems. Thank you!!!
    – Dennis J
    Apr 26, 2020 at 15:33

1 Answer 1


Thank you to the many responses. I read them on the cell phone early this morning, but cannot find them here on Ask Ubuntu. So now I need to learn how to find those excellent responses to give credit where it is due.

The answer was: Use Shift to bring up the GRUB menu, then F6 in order to select "nomodeset".

Again, many thanks. 20.04 is installing now on my test PC.

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