I recently (Saturday) updated Quicktime and iTunes for their recent
security update. To cut a long story short, the iTunes install failed
while it was installing Quicktime, leaving Quicktime not installed
according to Add/remove Programs, but with the directories and registry
full of it. Installing the previous version would not work as it said a
newer version was already installed.
After many hours spent ripping Quicktime out by hand, trying again, and
repeating the process, I've found the answer, which I will repeat here
for anyone who finds themselves in the same boat. (BTW, this came from
one of a number of posts on the Apple discussion board, but for most
people, other things seemed to cure it. Maybe x64 is slightly different
in this regard.)
The problem is KB908531. Yes, *that* one, the one which hosed a number
of other things a month or so ago.
I tried removing KB908531 (from Add/remove Programs), but it warns about
KB911562 and KB912812, so I removed them first, and then KB908531.
iTunes and Quicktime then installed and worked. Next I had Microsoft
update reapply KB908531. After this iTunes crashed, and Quicktime
started then vanished with nothing ever apearing on the screen.
I then removed KB908531 again, and now iTunes and Quicktime work again.
I will now try reapplying KB911562 and KB912812 without KB908531 and see
what happens.
Graham.