The latest beta (test) version of Microsoft Windows – currently known as “Windows 7” – leaked to the Internet just before Christmas. Millions have downloaded it illegally… but you might want to hold off on actually installing it. Microsoft recently admitted to a bug in the included Windows Media Player 12 which can delete the first couple of seconds of every mp3 file it plays!
What actually happens is that Windows will corrupt any MP3 file with a header larger than 16KB if that file’s metadata is overwritten. So your data will become corrupted if you manually edit the ID3 tags in Windows Explorer *or* have WMP set to automatically fetch the artwork and other information over the Internet (which is the default setting if you picked the “Express Setup” of WMP 12).
This bug applies to leaked build 7000 of Windows 7 only. It does not apply to any other Microsoft operating system, or any other build of Windows 7. Although Microsoft is working on a patch for this, you can avoid it completely by not using WMP12 or using any built-in tool for editing metadata. Risk takers are advised to turn off the “download artwork” option if they must use WMP12 in Windows 7.
Read more about it here.