Most recent fixes patch flaws in the operating system, but they also break support for some applications.
Apple released a large security update for Mac OS X on Monday. Security Update 2005-007 provides fixes for flaws in various parts of Apple's software, including the Safari browser, Bluetooth wireless and various networking tools.
But the update doesn't just fix security bugs; it also breaks support for 64-bit applications in the operating system, according to Wolfram Research, maker of the Mathematica computation software. It's unclear whether applications other than Mathmatica's are affected.
"Due to an error on the part of Apple, this update prevents any 64-bit native application from running," Wolfram told its customers in an e-mail alert on Tuesday. In particular, the problem means that Mathematica 5.2, released in July, will not run on a G5 computer with Mac OS X and Apple's latest security update, according to the e-mail.
Apple is aware of the issue and plans to fix its security update, Ben Wilson, a Wolfram spokesman, said in an interview on Wednesday.
Apple did not comment on the problem Wednesday, but early Thursday morning the company said it had released a new security update that fixes the issue.
"We have issued a new version of the 2005-07 security update which resolves an issue affecting 64 bit applications," an Apple representative said in an e-mailed statement.
The new update is available through Apple's Web site. Users who have already installed the earlier update should install the new version as well, according to Apple's Web site.