I’ve found out that the source of Mr. Allchin’s concerns was 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.
Vista seems mostly on track, although every day it ships past Wednesday will mean one less localized version for the January launch. Personally, I can’t wait for the moment we can officially say that Vista is done.
UPDATE: Mary Jo Foley talked to a bunch of top testers to get their feelings. The general consensus is that while there are issues with Vista, it is ready to and needs to go out now.