It's just the way of Linux, especially on legacy hardware: every now and then you screw things up beyond repair--like when you change graphics drivers and can no longer access a login screen. I recently got myself in a pinch and, after hitting my head against a wall for several hours, decided that I'd look at reinstalling Ubuntu and restoring from a Duplicity/Deja Dup backup. Unfortunately, my first attempts to restore the backup presented me with an error that seems to be somewhat common. The fix, as often seems to be the case, was a simple permissions change.

This is probably a no-brainer for advanced Linux users, but for newbies it may strike as awkaward that if you create/partition a disk with one user on your computer, another user won't automatically have "access" to it. This is a good opportunity to revisit the function of permissions in Linux--a quick review of Users and Groups.