While loading the update, 4.0.1, I'm asked to format my disk, followed by a warning that formatting will lose all the files. WTF?
It asks me to format my disk, then warns me to fear formatting my disk. Tell me why I need to format my disk and why I won't lose everything on it? THIS IS ABOUT DOWNLOADING THE NEW UPDATE, NOT ABOUT OPERATING THE PROGRAM!
Alla svar (1)
This is from the automatic update system? That's really strange. (Maybe you last downloaded to a CD drive or something??)
If you are coming from 3.6.17 to 4.0.1, go ahead and download from the source:
Before installing, I recommend backing up your Firefox settings in case something goes wrong. See Backing up your information. (You can copy your entire Firefox profile folder somewhere outside of the Mozilla folder.)
And definitely don't format anything.