Fixing a bizarre iWork and Pages problem (with the SFWordProcessing plug-in)

Earlier today, I was using Pages '09, and I attempted to open a document that I'd opened many times before, though perhaps not since upgrading to either iWork '09 or Snow Leopard. Boom. Pages crashed (that's what happens when programs "unexpectedly quit") and the error message said “Pages quit unexpectedly while using the SFWordProcessing plug-in.” Searching for the error online showed several possible causes and solutions for the crash, but it appears to be a font problem, and often seems to be connected to the version of Hoefler Text that ships with Snow Leopard. It's also not limited to Pages; other iWork programs have the same problem, as does iWeb, which is part of iLife. The document that I'd been trying to open used that font.

I verified that the problem on my machine was with the Hoefler Text font by using Font Book to disable the font, then opened the problematic document in Pages. No crash, though of course the text that was in Hoefler Text now appeared in a different font. Turning the font back on in Font Book made the problem reappear.

Some people suggested that the solution was to replace the version of Hoefler Text that ships with Snow Leopard with a version that shipped with a previous version of Mac OS X, and they provided such versions for download. I didn't want to do that if I didn't have to, so I did some more digging. Here's what worked for me:

1. Restart your Mac.
2. As soon as you hear the startup sound, hold down the Shift key. This tells the Mac to do a Safe Boot. Instead of the regular startup sequence, you'll see a progress bar in the lower third of the screen. As part of the Safe Boot sequence, the Mac is doing a bunch of things (see this Apple support document for more detail), but the key here is that it is trashing the user font caches, which will be rebuilt automatically.
3. When the progress bar finishes, you'll see the Login screen (even if you usually have it turned off). Enter your password, login, and wait until you see the Mac desktop.
4. Restart again, this time normally (i.e., don't hold down the Shift key).
5. Fire up Pages (or whatever program is giving you trouble) and see if the problem has gone away. It did for me.