Paul Thurrott reports: ... an unexpectedly buggy pre-RTM build of Windows Vista that surprised the company. The previous Friday, Microsoft pushed Windows Vista build 5824 into escrow, hoping that this build could qualify as the final shipping version. But a catastrophic problem with the build destroyed any systems that upgraded from Windows XP, requiring complete reinstalls. After a frantic several days of trying to find the bug, Microsoft finally fixed the problem last Friday and reset escrow. Microsoft on Friday internally released build 5840, which did not include the problem. Testing over the weekend produced positive feedback.
Windows Vista build 5840 includes a surprising number of brand new and final icons, and Continue At Source