Copies of the current build of Mac OS X 10.5 – also known as 'Leopard' – have begun to leak on to the web.
Right now, a build of the OS (operating system) is circulating on filesharing networks, including BitTorrent.
The software, which claims to be a copy of the beta software distributed to developers at last week's WWDC (Worldwide Developer's Conference) event, began to emerge over the weekend.
Apple offered a ten-point public peek at its next OS at WWDC, and copies of the software were given to attendees at the show so they could begin tweaking their software offerings for it.
The company is likely to take a very dim view of the leaks. A similar incident last year saw Mac OS X 10.4 released without permission. Apple tracked down and litigated against the developers responsible for the leak.
Developers attending WWDC have signed strict and enforceable legal agreements not to distribute Leopard through filesharing networks.
Early responses from people claiming to use the software report that certain parts of it feel incomplete. Apple last week told the public that it intended keeping some features secret as Mac OS X heads for its showdown with Microsoft's Vista OS early next year.
Meanwhile, a Windows-focused website last week described some additional features that will debut in Leopard.