By Sam Oliver

Published: 09:00 AM EST

Apple last night pushed out another pre-release build of its upcoming Mac OS X 10.5.5 Update for the Leopard operating system, tacking on several more bug fixes to a list that swelled into triple digits a week earlier.

The new build, 9F13, arrives less than a week after Mac maker equipped developers with build 9F9 and warned of a problem with some images that could cause its Aperture photography post production software to unexpectedly quit.

Wednesday's release, however, is the first since the company launched the Mac OS X 10.5.5 Update beta program three weeks ago to arrive without the presence of known issues, people familiar with the software say.

Apple is reported to have made no changes to a list of two dozen core system components where developers have been asked to center the majority of their evaluation efforts.

Instead, the focus of build 9F13 gears towards maintenance and stability, harnessing ten more bug fixes aimed at strengthening the Leopard experience, bringing the total number of code corrections expected as part of Mac OS X 10.5.5 to an eye-catching 115.

Among the more notable tweaks are improvements to Power Management and Energy Saver settings for Mac notebooks, as well as a fix for MobileMe's DMNotification that has been causing the MobileMe preference pane to crash for some subscribers.

Also addressed in the latest build were problems with Mail Sync and Preferences syncing, multiple TCP connections and Application Firewall, and the BSD Kernel and HFS+ file system.

When Mac OS X 10.5.5 makes its debut in the coming weeks, Leopard users can also look forward to improvements to Safari's handling of PDF documents, fixes to Address Book's syncing of newly created contacts, improved Mail message storage, and tweaks to iCal Invitations and email invitations.

In its raw form, Mac OS X 10.5.5 Update currently weighs in at around 330MB.