Apple has indicated that the update is recommended for all users of the 20-inch and 24-inch 2, 2.4 or 2.8 GHz iMac models. The iMac Software Update 1.3 (Leopard) and iMac Software Update 1.2 (Tiger) They are available from the support area of the Apple website.
Apple recognized in early October that a software update was the cause of the crash. According to users, the iMac became unstable, requiring a hard reset to recover its operation.
Apple has indicated that it recommends that all users install the update using the Software Update mechanism or the direct download link.