Earlier Tuesday, Windows Update, Microsoft's primary update service, began delivering the first patch to Windows 7 since the company last Friday. The update fixes a flaw that shaves several seconds of audio from any MP3 file that's edited, including files modified automatically as users connect to the Internet.

"Without action on your part, all MP3 files that have large headers in your and Windows Media Center libraries are likely to lose some audio," Microsoft said in the it published Saturday, several days after it first posted the fix to its MSND and TechNet subscription services.

, users who wanted to apply the fix had to find it, download it manually and install it themselves.

Microsoft also recommended that users back up all MP3 files before doing an upgrade to Windows 7 from , and that they set all of them to "read-only" status by right-clicking each file in Windows Explorer and then clicking the General tab and selecting the "Read-only" box. Failing that, users should disable metadata automatic updates in Windows Media Player, Microsoft said.

At the same time, it quashed the MP3 bug, however, Microsoft ignored a vulnerability in the Server Message Block (SMB) protocol that affects every version of Windows, including Windows 7.