The charmingly-named, and very informative, Woody's Office Watch sends out a free frequent newsletter with inside dope about Microsoft products. (Sign up page here.) The latest one contains this caution:
5. OFFICE 2007 BETA 3 IS NIGH
Sometime soon, perhaps even by the time you read this, the final public beta of Office 2007 will be released. Microsoft is calling it a 'Technical Refresh' but we'll continue to call it what it really is 'Beta 3'.
If you have Beta 2 (and millions are running it now) you'll want to switch over but don't rush. Most likely the changeover will require an uninstall of Beta 2 before installing the newer version. Even if an 'upgrade' is supported, past experience suggests that it's better to uninstall and reinstall instead of installing one test version over another.
Download 'Beta 3' / Technical Refresh but wait a few days to see if there's any major problems. In other words, let other people be the initial guinea pigs. We'll report on Beta 3 and let our readers know.
Without revealing too much, let me say: Boy, are they right! Installing this latest "Beta 3," on top of Beta 2, can have catastrophic effects. I don't know the exact sequence of events that can lead to destructive corruption of Outlook's .PST files -- but whatever that sequence is, I have been through it. If you have applied Beta 2, and have not yet tried Beta 3, heed the words of Woody: Don't rush.