A couple of users have complained of the following problem. After they upgrade their system to 10.2.4, certain apps stop working. In one case, the OpenGL library was deleted, in another, a library necessary for running Carbon apps like IE vanished. In each case, the solution was to download the standalone updater for OS X (10.2.4 combo update) from
Apple Featured Updates and install it.
[
robg adds: Based on user comments on sites such as MacFixIt and Macintouch, the Combined Updater does seem to help those who experience problems after using the usual Software Update updater. I have no idea why this might be, but it seems like more than an urban legend...]