I used preupgrade today to upgrade from F9 to F10. After downloading all the packages, it asked me to reboot. After it did so, anaconda was started, and there were several message that came up.
1. "Unable to mount hda6 to /mnt/hda6" - I thought it isn't important, so I clicked on Continue.
2. "Downloading repository information from repository"
3. "Retrying downloading"
4. "Unable to read package metadata. This may be due to a missing repodata directory. Please ensure that your install tree has been correctly generated.
Cannot retrieve repository metadata (repomd.xml) for repository anaconda-InstallationRepo-200811191949.i386. Please verify its path and try again." The options were Exit Installer, Retry, Edit, and Continue.
When I clicked on Edit I was prompted to enter a path to the repository. However, there was a popup that said "Unable to display /Nothing/var/cache/yum/" - which may be a hint to someone who knows these things.
When I tried "Retry" it said "unable to generate install tree".
Help! I'm so close to getting F10...