The issue, according to Dave Massy, a senior programming manager with Microsoft's IE development team, is that Netscape 8, which released just last week, breaks IE's ability to render some XML (Extensible Markup Language) pages.
"We've confirmed that after installing Netscape 8, the XML rendering capabilities of Internet Explorer no longer work," wrote Massy in an entry to the IE team's blog.
Some pages, including RSS feeds, which use XML, appear blank in Internet Explorer after Netscape 8 is installed. Although Massy didn't specify which versions of IE were affected, TechWeb confirmed the problem on systems with IE 6 running on Windows XP SP2. Massy offered up a Microsoft XML-based page as a sample.
Users' immediately weighed in with theories as to the cause of the bug, with comments posted to Microsoft's blog ranging from the dubious to the supportive.
"I really don't want to sound cynical, sarcastic or satirical, but that is one hell of a way to prevent users from switching to another browser," wrote one user identified only as "snowknight."
Talk like that quickly set off others. "Cue endless conspiracy theories about MS's 'dirty tactics,'" retorted reader Chris Beach.
Massy only threw fuel on the fire by saying that in order to fix the problem users must uninstall Netscape.
"That's just silly," said America Online spokesman Andrew Weinstein when asked about Massy's recommendation. "This is a very minor issue. The average user is never going to see an XML page. The only users who potentially might see this as a problem are programmers and developers. For the average user, it's zero."
Even so, Netscape online support representatives said they were sorry for the screw-up. "We apologize for the inconvenience that this bug has caused you," one wrote on the Netscape Brower Review forum. "This certainly isn't desired behavior. The development team is hard at work on a patch."
Weinstein confirmed that a patch was in the cards. "We're working on a fix, and should have something ready for auto update next week," he said.
Netscape 8 has been touted by AOL as a more secure browser than either IE or Microsoft's main rival, the Mozilla Foundation's Firefox. In fact, while Netscape 8 is based on Firefox code, it also uses IE's rendering engine to display some Web sites.
One of the mysteries of the Netscape goof is that in order to correct the problem, users must not only uninstall that browser, but also must manually edit the Windows Registry, a scary thought for most users, and a practice even Microsoft traditionally warns against.
"If Netscape 8 remains installed, then the registry key is continually rewritten," said Microsoft's Massy in explaining why users had to muck in the Registry.
"We didn't intentionally change that registry key," said Netscape support.
"I don't know why the key was changed," said Weinstein. "But I imagine, since Netscape uses IE's engine, that it's to do with that."
This is the second embarrassment to Netscape in as many weeks. Just hours after it launched on May 19, AOL updated the browser to patch three security vulnerabilities in the Firefox-based code.