I backup daily to a USB drive, at work with git push. But the last couple of days, I've been home, sick.
I called in to ask Mike to stick in my USB drive, and he did, but it didn't automount. The automounting seems to be a Nautilus thing, and requires being logged in at the console. (I lock my screen when I leave at night.)
I made him a login, so he could get in, and that got us farther, but when it mounted, it was owned by him.
I tried mount -o remount,uid=1000, but that didn't work. The mount command showed two uid= arguments -- the first, his. (If I did it again, there were three. The first one was still his, so he still was owner.) Okay.
I jotted down the name of the device, /dev/sd1, unmounted it, and remounted it by hand, as me. Ta-da.