Corruption! (in data, not politics)
For some reason, some files on my USB drive became corrupted. I ran chkdsk, and that recovered most of the files, but some were deleted! The really bad thing about it is that the prefs.js file for Fx is gone, and while I was able to get most of my preferences set, some will not stay.
I can't customize my toolbar. I can change things, but I'm back to default when I open Fx again. I made sure that prefs.js and user.js were writable. It's quite odd because my status bar icons were out of order, and I was able to rearrange them and keep the settings, and I was also to change the theme, which also stays.