1) Download Nightly 2) On a normal NTFS volume, create a directory, assume G:\Nightly 3) Launch Installer, select custom install 4) Point installation dir to G:\Nightly 5) Installer fails and exits with "not enough diskspace". Window shows x Megabyte needed, yGigabyte free. 6) G:\Nightly has disappeared. I found this while trying to reproduce an issue reported by a user that had Nightly on a seperate disk and complained about being unable to update recently.

I see this randomly (and rarely). And saw it just now. Can't reproduce. 1. custom install 64 2. alt+n, alt+c, alt+n 3. highlight "\nightly" 4. set location to C:\Program Files\mozilla.org\FF 19.0a1 2012-10-25 5. alt+n error message 800GB free on a 1T disk