All my adult life I've loved playing with beta software. I like it because -- well, it's new. You get a preview of the tools and tricks you'll soon be able to use. You can in effect look over the software designers' shoulders and see what problems they're trying to solve.

But here is what I have learned over the last ten weeks, through the worst experience of my 25+ years of using personal computers: be very, very afraid of beta software for any functions you need for actual work.

As mentioned earlier, the disaster involved the upcoming releases of Microsoft Office 2007 and Microsoft Vista.

I like them -- especially the new Office. It looks much nicer than its predecessors. It has a number of elegantly-applied new features. I was seeing the early versions for an upcoming column about them, which is positive -- as it should be.

But jeez louise! Ever since the fateful moment when I slid into my computer a CD containing the Office "Beta2 Tech Refresh," these conditions have prevailed:

* One of my laptops has been rendered unusable, and will be so until I do a complete "Format C:\" start-from-scratch overhaul.

* Another one, with an even newer beta release of Vista, does not work at all, because of a video-driver conflict between Vista and this machine. To be precise, it has never run for more than 20 minutes at a strech, between blue-screen "hard" crashes.

* If I made an appointment for tomorrow or copied down someone's address in Outlook, that's too bad, because I haven't been able to get at my Outlook calendar or contact lists since early September. (Thank you, Google Calendar!) Installation for betas of the new Outlook is a fateful one-way process: once you've applied the new beta, there is no way (short of a full system re-installation) to go back to a previous, working version of Outlook.

* Those files I've been amassing for the last two years in the wonderful OneNote program? Can't get at those either, because the latest betas of Office do not include OneNote -- and there is no longer a way to install it separately. Only alternative is to wait for the full, official release.

* Microsoft graciously sent install disks for WindowsXP and OfficeXP, so I could bring my computers back to a functional earlier state. But they sent them as if part of a formal commercial export to China, making them subject to import duties of about $200 and, so far, a three-week delay in Chinese customs. Thanks, but....

Microsoft's final release software is amazingly stable, considering how many oddball configurations it must run on in every corner of the world. None of this is really Microsoft's "fault," since they've tried to be helpful (a number of emails from them begin "Sadly,.." ), since half the problems arise from my being in China, and since they point out that this is, after all, pre-release beta software. From now on I'll take that warning seriously. When the real Office 2007 comes out, I will buy it. And I will use it until the real, authorized version of whatever comes next -- no more betas of important software for me.

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