16.04 Installation crashes with separate home partition

[Giampiero Salvi]

I had Ubuntu 14.04 on my system with "/" and "/home" mounted on different partitions of the same disk. I tried to upgrade to Ubuntu 16.04 and the system became unbootable (kernel panic at start up). The I tried to install from a usb live disk. The installation lets me choose the same partitions as "/" and "/home" and it gets past the definition of the user and machine. After a while it crashes without explanation. The first time I tried without reformatting the partitions, the second with formatting but nothing changed (besides all data being gone under /home, but I had a backup).

I trust the bug reporting system is going to attach all necessary extra information.
Best
Giampiero

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubiquity 2.21.63.2
ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13
Uname: Linux 4.4.0-31-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.4
Architecture: amd64
CasperVersion: 1.376
Date: Wed Jan 18 12:09:20 2017
InstallCmdLine: file=/cdrom/preseed/ubuntu.seed boot=casper initrd=/casper/initrd.lz quiet splash --- keyboard-configuration/layoutcode=se
LiveMediaBuild: Ubuntu 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160719)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: ubiquity
UpgradeStatus: No upgrade log present (probably fresh install)

[Giampiero Salvi (giampisalvi)]

I can add that I tried the standard installation (erasing the whole disk) and that crashed as well, so it is not a problem with the different partitions for "/" and "/home".

[Giampiero Salvi (giampisalvi)]

Apparently the problem was that the installation program could not cope with a RAID array that I had in the machine (but that was not used to install). I disconnected the two RAID disks, and the installation went smoothly.

I wonder if this is something that can be improved: I selected the non-RAID disk for the installation, and the partitions ended up on the right disk, but something went wrong after that (possibly the installation of grub?). In one of the many attempts I received a specific error about grub-install failing on /dev/sda (that is one of the two RAID disks). However, none of the choices I got to solve the problem worked: I could choose the right disk (/dev/sdc in my case), install without grub or abort the installation, but whatever I choose, pressing OK had no effect.

Also in all the other attempts, I did not receive the grub-install error, but just a generic crash report.