Hi, The mistake was EFI. The source CentOS 7.7 machine was EFI boot. and the destination CentOS 8 VM was non EFI. Made a VM snapshot and wrote a script to install the packages one by one and reboot each time. The VM crashed at grub2-efi-x64.x86_64 thanks. -- Thomas Stephen Lee On Wed, Oct 16, 2019 at 8:05 PM Ljubomir Ljubojevic <centos at plnet.rs> wrote: > On 10/16/19 4:05 PM, Jonathan Billings wrote: > > On Wed, Oct 16, 2019 at 04:00:20PM +0530, Thomas Stephen Lee wrote: > >> Failed to switch root: Specified switch root path /sysroot does not > seem to > >> be an OS tree. os-release file is missing. > >> > >> What am I doing wrong? > > > > Tested, and yes, this happens after a reboot, grub2 isn't giving the > > initrd a root disk to switch to. > > > > I had to edit the grub.cfg and add a single line, > > set default_kernelopts="..." > > > > (using what was GRUB_CMDLINE_LINUX= was set in /etc/default/grub) > > > > I'm not exactly sure which package that was installed that caused > > this. > > > > Create a snapshot of clean VM and divide that list in 10 pieces and > install them one at the time and reboot afterwards. If VM boots, create > another snapshot. When it fails, reverse to previous snaphot and divide > that segment into 5-10 smaller pieces, rinse and repeat. > > -- > Ljubomir Ljubojevic > (Love is in the Air) > PL Computers > Serbia, Europe > > StarOS, Mikrotik and CentOS/RHEL/Linux consultant > _______________________________________________ > CentOS mailing list > CentOS at centos.org > https://lists.centos.org/mailman/listinfo/centos >