I just tried installing XPIze 4.0 on a W2kProSP4 that I had on a spare hard drive, and I don't get the weird black borders around the icons (though I also don't get any XP icons, either). I installed it after patching so 256-color icons can show up in the taskbar, if that means anything. My logon screen was similarly patched to read XP Pro, and the time zone settings map looks nice. So far I haven't seen any strange visual artifacts, but I'll put it through its paces to see what's what. EDIT: Ah, yeah, there the artifacts are. XPero, do the bitmaps you use contain alpha information (that is, do they use alpha blending)? Win2k should have no trouble displaying 32-bpp bitmaps (and it can technically perform alpha-blending, just as XP can), but it might not be calling AlphaBlend() to display them, which would preclude using bitmaps that relied on alpha-blending. Win2k can handle high-color icons, but it might require a version of XPize where the alphas were only 0 or 255. It's possible that Win2k simply calls something like MaskBlt() to display icons, which requires a monochrome mask (that is, alpha = 0 or 255 but nothing else). EDIT #2: I found the spec on the .ICO format and wrote a program that can read all the icons in a file and display them. Looking at the icons in the XPize folder, it looks like that's exactly the case, where the icon is performing alpha-blending (technically, the AND-bitmap in the .ICO file extends over areas where the alpha value in the XOR-bitmap is less than 255). Tomorrow I'll see if I can write a program that will recursively go through all of the .ICO files in the XPize folder and "fix" them for W2k. My gut tells me that, when alpha is 128 or higher, to add enough white background so I can make the alpha 255, and drop all pixels where the alpha is 127 or less. I'll know if it works sometime tomorrow night. I haven't even tried the XPize settings program to see if I can get it to reload the icons once I've changed them, but I assume that that's what it's for.