Help me track where this preference is stored (reverse sceen colors ctrl-opt-cmd-8 )

[Paul F.]

SO here's the backstory... before getting to the problem.

Students are clever... students are, shall we say, destructive when bored.

Students discovered the ctrl-opt-cmd-8 keystroke that toggles the screen to reverse colors (also in the Universal Access pref pane).
Fair enough... I missed that "hole" in my 10.4 "model" install.
So I rolled out a fix that removed the keystroke from the Keyboards->shortcuts pref pane.

That worked for a couple months. Now, as of yesterday, some student(s) have found a way to change the screens to the "negative" some other way which I have not yet discovered.

Problem is, in the "student" account on the computers, there is NO access to the System Prefs application, no permission to change system preferences, and the keyboard shortcut is disabled.

So not only can I not figure out (yet!) how they're doing it, but I can't change it back!

The ~/Library/Preferences/com.apple.universalaccess.plist file has not been changed from the "model" install (I replaced it on the affected machines, to no result...), and the problem is limited to the one user- so it's in there someplace!

I'm coming up short being able to find exactly WHAT preference file is being modified (that, apparently, I have not yet locked to be unmodifiable... ) so I can UNDO it without the keystroke being active!

Ideas?
Anyone?

Thanks :-)

[lost in space]

Paul,

Not an answer to your question, but....

I may have suggested this already, but have you looked into Deep Freeze? We've used it for our Win and Mac lab computers for years. I don't think we'd last one hour without it. Works on 10.4 and up, includes remote control app for locking and unlocking. It's been a long time since I bought it, but I believe they have education discounts. faronics.com

No affiliation, just depend on it like life support.

[Paul F.]

I think I'm on to something!

the com.apple.CoreGraphics.plist is only present on the messed up machines!

[Paul F.]

Yup... that's it!

DisplayUseInvertedPolarity "Yes" or "No"...

So now I can fix it (and prevent the future occurences).



Lost in Space;

I have looked into Deep Freeze, and it seems a fine product! But too expensive compared to using some simple tricks to lock preferences, login scripts, and the like...
This is the first time students have really gotten ahead of me aside from the occasional time when I just forget to lock something...
I'd love to be able to use Deep Freeze... but the budget just isn't there.

[lost in space]

Paul F. wrote: ... but the budget just isn't there.

I know the story.

[C(-)ris]

Now the question is, how did they change it...

[Paul F.]

C(-)ris wrote:
Now the question is, how did they change it...

An excellent, and still unresolved, question!

But at least now I have locked that preference file so it cannot be modified in the future!
Just have to push "chflags uchg /Users/student/Library/Preferences/com.apple.CoreGraphics.plist" to the whole campus using Apple Remote Desktop.