Sometimes you may make the decision NOT to update a piece of software for a while due to incompatibilities or wanting to keep all machines at the same version until such time you release a new company image. The procedure to hide Apple software updates has now changed in Mountain Lion.
Now that ALL Software Updates are managed by the Mac App Store and not a combination of Software Update and the Mac App Store, the way you ignore specific software updates requires selecting to ‘Hide’ the update in the Mac App Store.
This feature only works for system software updates and NOT App updates :
- Open the Mac App Store application and look under the ‘Updates’ tab.
- If you control-click or right-click on an item under the Software Update list, you can choose ‘Hide Update’.
The update will now be hidden from the list of available updates in the Mac App Store.
To reverse this :
- Back in the Mac App Store application, click on the “Store” pull down menu and select ‘Show All Software Updates’.
- If you quit and then reopen the Mac App Store application, all hidden updates will be available again under the “Updates” tab.

This feature has been tested using OS X v10.8.2 which was the latest Mac OS release at the time of writing and also using the latest Internal and external Apple keyboards.