Now it can be told: Microsoft dropped off a close-to-RC1 version of Windows Vista Ultimate here a few days ago and I immediately installed it as an upgrade to Beta 2, which I've been running for several months now.

But while the true RC1 (Build 5600) may be a big improvement, my upgrade experience (with Build 5568) has been less than joyful. Nothing has been truly catastrophic, mind you, but I have encountered a lot of irritating quirks.

The first thing that happened involved a bit of dual-monitor confusion. I have two 17in LCDs, and after the upgrade the former monitor 1 inexplicably became monitor 2 and vice versa. More annoyingly, only the former monitor 2 (now monitor 1) came to life after the post-upgrade reboot, and my mouse would not control anything in that window.

Fortunately, a reboot revived my mouse and while my monitors are still reversed, I was able to get things working the way they used to by flopping monitors 1 and 2 in my display settings (which in Vista are obscurely accessible through the vague-sounding Personalize icon in Control Panel).

The reboot (and subsequent restarts) produced another irritant: a window telling me that Vista couldn't find drivers for my Unknown Device. So something isn't working - but what? Your guess is as good as mine.

I got another little surprise when I first launched Internet Explorer 7.0, post upgrade: an error message popped up - something about a toolbar not being supported. However after I checked a box asking not to be bothered about the problem again, the message stopped appearing. I also have had no problem launching IE7.

I did get a scare the first time I tried to access the web-based tools for adding and managing content for a website. I had to log in, something I haven't had to do in a long time, and Vista wasn't accepting what I thought to be my usual user ID and password. Apparently the upgrade removed all my stored intranet log-in info, or some such. It took a while - and a conversation with one of our IT pros - to figure out the proper log-in format.

The good news: all my mission-critical applications (Word, Excel, Adobe InCopy, the Trillian universal instant messaging client, and the Palm HotSync Manager for my Treo 650) are still working. But they were working in Build 5384. And the apps I've missed most - Rhapsody, Adobe Photoshop Elements 4 (which for some reason won't accept the serial number on its package as valid in format!), and the Palm desktop and installation software -still don't work.

I'm also seeing one disheartening degradation in functionality: When I launch an application that for some reason doesn't play nice with Vista's Aero graphics, they go away completely (previous I still would get Aero Glass on windows for the other apps). And I still get occasional momentary total screen blackouts.

All in all, my close-to-RC1 build doesn't feel like a big improvement so far. Hopefully, the kinks will go away, or Microsoft will straighten them out in the final leg of development.