Comment 26 for bug 1507505

Experiencing a similar problem here using 18.10 64b on a laptop featuring 2 nvme-drives.
Installation was started through legacy bios (UEFI off) and proceeded simlilar to #23:
1) Select manual partition setup
2) install to blank /dev/nvme0n1 is blank
3) create a partition at front of drive, 500MB , mapped to /boot
4) create "physical encrypted partition" following the boot partition of 80 GB
5) assign new encrypted partition with the / mount point
6) select /dev/nvme1n1 (yes, this is THE OTHER DRIVE, because win10 resides on this one and this is the drive set as primary boot-device in th BIOS setting) as the partition to install the boot loader.

Grub-installation then fails and a dialogue asking how to proceed is shown with the options:
A) choose a different device to install the bootloader on (with a drop-down list showing all disks and partitions present on the system but neiter re-tying to install on nvme0n1 nor nvme1n1 succeeds)
B) continue without a bootloader
C) cancel the installation

I suspect my issues are related to not using UEFI in conjunction with installing on a nvme-drive rather than cross-installing the bootloader to a differing nvme-drive from where the ubuntu-system resides on. I'll try to install via UEFI next and check out #14...