UAC is not user specific but a global setting
I'll make a guess. I don't run Vista with UAC off so I haven't tested this.
With UAC on when the misbehaved program wrote to system files areas or
system registry settings the operations were redirected to the virtual store
for that user. With UAC off you lose the benefit of this extra security and
the misbehaved program can do whatever it wants possibly trashing your
system in the process.
It seems some here still cling to a simplistic view of UAC's feaures
and purpose. Moving files or folders from one non system location to
another can't possibly be considered a "threat" to the system and
isn't "misbehaving" yet UAC at times will nag you to death if you try
or even simply try to delete such files, IF some application is seen
by Vista as "owning" the files then way too often UAC steadfastly
refuses to allow you to change the permisssions no matter what you do
short of turning UAC off. I don't view such heavy-handed inteference
as a "feature" and you wouldn't either if you had to deal with this
type of issue constantly.
As far as "security" that is a red herring. Source: Microsoft. People
need to educate themselves on what IT professionals, seasoned users
and Microsoft itself admits to regarding the failings of UAC. Such
things aren't often posted to newsgroups like this. Explore for web
and LEARN.
The intended real purpose of UAC is to educate users of the risks
running at administrator level. UAC does not prevent that, rather it
simply (if working correctly, which it often don't) pops up a warning
then if you are a administrator allows you to proceed or under some
situations allows you to elevate a process to have administrative
rights to do what you were planning on doing anyway. People that view
such mickey mouse features as real security don't have even a basic
understanding of security issues are all about.
The myth some here seem to be foolishly perpetuating is if UAC is in
it's default "on" condition somehow your system is safe. Since UAC
pops up usually when you are in the middle of trying to do some task,
human nature being what it is people will continue to do what they
intended to do and often nothing stops them except for UAC asking you
to confirm want you want to do. This quickly leads to people just
clicking through every time a warning pops up and is the electronic
version of crying wolf. In short order, nobody pays any real attention
to the UAC nag warnings, thus defeating the purpose.
That leaves us with all the false "security" warnings UAC has a bad
habit of nagging about, which quickly becomes an annoyance. Again how
often you see these things depends on what your use your computer for.
