Mostly note to my self for futu­re reference.

What they don’t tell You in the tar bac­kup tuto­rial is that it’s not eno­ugh to edit /etc/fstab (and the­ir instruc­tions for grub are for grub-legacy).

Becau­se after resto­ring you pro­ba­bly have new par­ti­tion UUIDs, you must:

• boot livecd
• mount your root fs
• mount -B /dev /rootfs/dev, etc. (with proc and sys at least) to be able to chro­ot from livecd to your root fs
• chroot /rootfs
• edit /etc/fstab and chan­ge UUIDs the­re (new ones you can get using blkid
• do sudo dpkg-reconfigure -plow grub-pc to auto­ma­ti­cal­ly upgra­de grub con­fig files, just let it install to the drive(s) it was on
• do update-initramfs -u so UUID sto­red insi­de ini­tramfs get upda­ted, too

Then you sho­uld be able to boot it.

Install Vir­tu­al­Box Guest Addi­tions in Win­dows’ safe-mode so sys­tem file pro­tec­tion doesn’t inter­fe­re with the instal­la­tion, it’s that sim­ple and fixed all my Vir­tu­al­Box per­for­man­ce problems.