I have not needed to boot into 9.2.1 since I got X.1, except for last night: I totally screwed up my dock by accidentally using an older version of Trasparent Dock (meant for 10.0.x, not X.1) to revert the dock to its original state (which the just released new version of T.D. says you must do, using the last release of that program, but I accidentally used the original version) and since I had forgotten to remove my old 10.0.x dock backup, I accidentally replaced the X.1 dock with the 10.0.x dock while using the wrong version of T.D., so I needed to replace the dock. Not knowing how I could do this, I tried going through the install CD, hoping that if I removed the dock altogether and ran the installer, it would replace the dock and be done with it. No such luck: not only did this not work, but all my users stopped working, so I started from scratch, and messed up. In the end, I backed up the important stuff on the external drive (mostly apps) and did a reformat-clean-install of OS X, with NO 9.2.1! I decided that since 9.2.1 works just fine on the Firewire drive, I don't need an extra copy taking up space on my internal drive. The only thing I regret so far about this clean install is that I did not set up a separate swap partition like so many people recomend. I feel so free! My machine is not tied to the old OS anymore! I don't need it, I have it when I choose to use it, but it is not there at the root directory, reminding me of its oldness. Anyway, it was a long night, what with reinstalling X.1 twice, then re-updating the system, and re-downloading iTunes 2 (it was replaced with the older one the first time I ran the install CD for OS X.1