Apple's new operating system, 'Mavericks' was released yesterday for free download. District faculty and staff should not update district-owned computers with the new operating system unless cleared to do so by the IT director but if you have already upgraded a personal computer, you may be running into yet another problem opening the PowerSchool Gradebook.
One feature of the new OS is Gatekeeper, which Apple claims will help keep your computer free of malicious software. Unfortunately, Gatekeeper doesn't yet recognize Pearson as a developer so clicking to open Gradebook will generate an error message saying that the program "can't be opened because it is from an unidentified developer."
To get around this, click 'Launch Gradebook' as usual, then go into your Downloads folder and control-click the downloaded application file. Choose 'Open With-->Java Web Start'. If prompted to update Java at this time, skip the update (that problem hasn't gone away yet, either!) and then confirm that you actually want to open the program.
This link from Wikihow explains in more detail how to bypass Gatekeeper.
This link from Wikihow explains in more detail how to bypass Gatekeeper.