Adobe fouls up yet again.
Just as Lightroom was turning into a professional product, Adobe introduces Lightroom 4 (Beta) - and failed / refused to get it running on the most popular version of Windows - XP.
It even runs on the most disdained iteration of Windows - Vista, but not on the most popular version - XP.
Now, I'm not a fan of Windows, but - Adobe -- you've got to be kidding.
How do they do it ? Adobe gets so many things almost comically wrong I'm wondering if they are auditioning to be a government agency.
All of the other PC Raw development programs run on XP. (Aperture and DarkTable do not - as they are Mac, not PC, programs)
Better Alternatives: If Adobe just slammed the door in your face, let me urge you to try DXO, Silkypix, Capture One, RawTherapee (which is free), DCraw, DPP, PixInsight, LightZone, Bibble . . . and see some marvelous Raw development capabilities that you might not have realized existed.
As an expert on Operating Systems with a fairly expansive imagination, I am confident there is absolutely nothing that Lightroom can do on Vista - that it can't do on XP.
That means this is just a lazy choice by Adobe "management." They decided they don't want to spend a little effort to support you who spent good money on Lightroom versions 1, 2 and 3 to run on XP.
(Side note: Adobe doesn't even warn you Lightroom 4 Beta won't run on XP; at least not on their website. You have to first download the 400 megabyte program (Can you spell "Bloatware?") and try to install it. Only then do you get a notice that you have to upgrade to Vista. OMG ! Even PC Magazine fails to note, or realize this "feature.")
I'm relieved that I won't have to deal with Adobe again. The best part about leaving Adobe is I don't have to put up with their dysfunctional institutional arrogance.
The Lightroom team avoided this disease for a few years, but it finally caught up with them.