10 Replies Latest reply: Apr 7, 2009 1:23 PM by mkorth
mkorth Level 1 Level 1 (0 points)
I work with many labs in a high school full of eMac computers running OS 10.4.11 and am having trouble will Universal Access features. The features are great for the users who need them, but in many cases make the computer unusable by users who don't unless someone knows the shortcuts to toggle that feature.
Even in a managed environment (using Workgroup Manager locally on the machine to manage accounts) users are able to use the shortcuts to invert the color, turn voiceover on, and zoom.

Does anyone know of anyway to disable Universal Access completely?

eMac, Mac OS X (10.4.11)
  • Kappy Level 10 Level 10 (260,490 points)
    Open the Universal Access preferences. You can disable any or all of the Universal Access features.
  • Limnos Level 8 Level 8 (44,555 points)
    Kappy has a suggestion but I am not sure if it just turns off the feature temporarily and it can be toggled on again with the keyboard shortcuts. There's one set of shortcuts to toggle the feature and another to use them once they are toggled. The toggling feature overrides whatever is set in the preferences pane. Maybe activating the parental controls feature (which I have never used) lets you lock the settings.

    If Kappy's suggestion doesn't work, alternative things to investigate but I have no idea if these are good ideas are:

    In /System/Library/PreferencePanes there is one labeled universalaccess. I don't know if removing this will disable UA or, as I fear, just the ability to change the preferences (which are stored in the apple.com.universalaccess.plist file), and the keyboard toggle shortcuts may still remain.

    Removing com.apple.universalaccess.plist will just cause one to be created again. I don't know if one were to edit the plist so the toggle key combinations were changed to some invalid values and then the file were to be made read only if this would lock it (or maybe lock your system!). Maybe somebody with more familiarity of the details of the system can come up with ideas.
  • Kappy Level 10 Level 10 (260,490 points)
    All of UA's features can be individually disabled if need be. None are enabled by default. Deleting the preference file should simply result in UA returning to its default configuration with all features disabled.
  • Limnos Level 8 Level 8 (44,555 points)
    Deleting the preference file should simply result in UA returning to its default configuration with all features disabled.

    Yes, but these features can be toggled on again without using the panel. The issue is how to stop people from toggling them on again. Setting Parental Controls to no let people have access to system preferences once having disabled all the features in the UA panel might be the easiest way to achieve that.
  • Kappy Level 10 Level 10 (260,490 points)
    Yes, I agree. That would be the only solution on a permanent basis. Either that or remove the preference pane, but that would not be the most desirable solution.
  • Limnos Level 8 Level 8 (44,555 points)
    Either that or remove the preference pane

    I am not sure that would work in this case since it is not clear the pane itself is essential in altering the preferences which can apparently be toggled by key combinations. If the pane simply acts an a GUI application to let you alter the settings in the preferences file in a window and the actual key encoding to alter the preferences is stored elsewhere then removing the UA pane would only remove the GUI and not the keyboard method for altering preferences. In other situations where the preferences pane is the only way to alter a setting then I agree, removing the pane would inhibit altering the setting unless you directly edited the .plist file using the plist editor.

    but that would not be the most desirable solution.

  • Archie Robertson Level 3 Level 3 (690 points)

    I apologise for duplicating this post from the Leopard threads, but it's quite short! I suggest using this as a pedagogical opportunity.

    Turn on VoiceOver on one machine and blindfold a volunteer. This is more dramatic and will have a bigger impact than simply activating the screen curtain. Explain to the kids the use of VoiceOver and guide your volunteer through a simple task such as creating a postcard home in TextEdit.

    When they realise just how useful VO is, and at the same time how difficult it is to navigate a machine when you can't see the screen, you should have no more discipline problems. I think all you'll be left with is a sense of awe among the kids that such a thing is possible.

    And if you really want to shock them, try playing them some of the videos from the AssistiveWare site. I'd suggest using Anne's to give a short intro to the use of VoiceOver professionally, and then Marie-France's, showing just what an effect VO can have. As a tip on the latter, translate the message Marie-France types to her mother: "Maman, peux-tu mettre ma tête droite?" (Mum, can you straighten my head for me?). I'm certain the sheer punch of this simple message from someone so helpless as to be unable to put her own head in a comfortable position will put an end to any cynicism or amusement. Since most kids carry an iPod or similar device with them, you could then get them to plug the earbuds into their machines and try the basic steps for themselves—without interfering with each other.

    Finally, I'd also suggest that you post up a list of the shortcuts to turn on and off the various Universal Access facilities, with a brief explanation of the role and function of each.


  • Limnos Level 8 Level 8 (44,555 points)
    An intermediate step. Maybe attach a script to a logout hook to have it delete the preferences file on logout. That way it would be reset when the next user logs in.
  • mkorth Level 1 Level 1 (0 points)
    Ok. So turning the shortcut options off in System Preferences worked just fine. I am able to limit access to System Preferences from the Student account so users aren't able to toggle the boxes. The new problem is in my iMac INTEL Lab where the shortcuts are turned off, but using the shortcuts still toggles UA options on the Student account.
    Any suggestions?
  • mkorth Level 1 Level 1 (0 points)
    I guess you have to turn off the shortcuts on each account...