I have a problem similar to the one posted here.
I am attempting to install Ubuntu 18.04 on my Dell XPS 15 9575, which comes with Windows 10 Professional 1909 installed. I followed this guide.
I disabled the fast boot, as suggested here.
I disabled secure boot, as suggested here
I'm now able to enter the try ubuntu version and everything works fine, but as I go forward in the installation instead of the installation type option I expected, I get this.
EDIT: Following the answer of @Serhii Popov in this question and changing SATA operation from RAID to AHCI I finally achieved to have the hard disk visible to ubuntu. Once arrived at the installation type window I selected the "Install ubuntu alongside Windows Boot Menager", that it the first option I'm given. Once ubuntu was installed however:
I'm no more able to boot Windows. If instead of ubuntu I choose Windows Boot Menager when computer starts I'm not able to access windows and I get a blue error message.
When Ubuntu starts the keyboard, unless I close and reopen the physical screen of the laptop, does not work. Moreover, after a while I'm using the computer without problems, the touchpad stop working too. And finally, at every start I get a system error message.