The OSx86 Project website stated Apple had served it with a notice on Thursday citing violations of the 1998 Digital Millennium Copyright Act, and the site was reviewing all of its discussion forum postings as a result. The site has always aimed to adhere to copyright laws and is working with Apple to ensure no violations exist, according to a statement by the site administrator.

The other website,, was completely shut down. Administrators there could not be immediately reached for comment.

An Apple spokesman declined to comment Friday on the DMCA-based notices. The federal law prohibits anyone from distributing software or hardware that can circumvent copy protection mechanisms. The law has been criticized at times as being unconstitutional and too broad.

Apple does not authorize the use of its Mac OS on machines other than its own, and earlier this week, the sites posted links to the website of a hacker who claimed his software patches could be used to run a version of the Mac OS on a non-Apple machine.

The hacking endeavours are, for now, relegated to a small, technically savvy set, but it underscores a risk Apple faces if a pirated, functional version eventually becomes as accessible and straightforward as installing other software on a computer.

It’s a risk that became more apparent after Apple decided to make a historic transition from Power PC chips to Intel Corp.-based chips, the same type that its rivals use in predominant Windows-based PCs.

Apple so far has two Intel-based computers on the market and plans to migrate the rest of its Macs to the Intel platform by the end of the year.

The Mac maker had anticipated some people would try to crack its new Intel-compatible OS X operating system and deeply embedded some warnings to would-be hackers in the software, including one written in the form of a poem.

The OSx86 Project website, which was formed after Apple announced its switch to Intel in June 2005, was among the many Mac-user sites that posted a copy of the poetic warning earlier this week.