[plt-dev] PLT interacts badly with crazy new Windows "AppData\Remote" idea

From: Eli Barzilay (eli at barzilay.org)
Date: Tue May 4 14:30:26 EDT 2010

On May  4, Doug Williams wrote:
> I got bitten by that back in 2008 - I have a blog entry (
> http://drschemer.blogspot.com/2008/07/plt-scheme-on-vista.html)
> about my problems from back then. And, I think this (
> http://bugs.plt-scheme.org/query/?cmd=view&pr=9554) is the bug
> report with an audit trail of e-mails.

To summarize the problem: lots of windows applications want to write
stuff in their directory, and this was almost always possible.  With
the move to vista, they're trying to make things saner by protecting
these directories (actually, the default user is not as powerful as it
was on xp) -- and the result is that applications that expect to be
able to write stuff this way get broken.  The UAC solution is to
"divert" such writes to a user-local directory, so that when the
program runs on behalf of that user it has the illusion that it can
write there, only really it gets stored in the user directory,
unaffecting other users or the system directory.  As expected, this
works for many cases, and when it doesn't, the resulting confusion and
mess is amazingly effective.  (Practically all of the problems that
this leads to start with mysterious voodoo bug reports, which sound
utterly confused and impossible to recreate.)

> I'm not sure if the installer was ever updated to know about the shadow
> copy. Eli and Matthew (and probably others) identified the problem.

The installer (or uninstaller) cannot be fixed to deal with it -- as
usual, the immediate way to see this is to consider a system with
multiple users: if I uninstall, you won't like it if it makes the
system delete your files.

IIRC, there was some bit to set somewhere declaring that the
application is well behaved, and just disable the UAC "feature", and
I'm not sure if there were other problems in turning it on.

          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!

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