Apple is closing in on its deadline for the introduction of its latest operating system, Mac OS X 10.5, 'Leopard'.

The company this weekend distributed the latest pre-release build of the OS to developers, with AppleInsider reporting this release as being a "full-blown build that appears as if it could be a candidate for release."

Build number 9A559 is described as containing just two "known issues", and seems to reflect the company's proximity to the release of the system to manufacturing.

Two known problems involve archive installs from Tiger, which may fail on some PowerPC Macs, while another fault involves HP printers. Apple has suggested fixes for both problems.

The company has already committed to releasing its new operating system next month, October 2007.