The mother of all leaks has just happened: Windows 8 Release Preview has hit the web ahead of its official debut. A Chinese edition of Microsoft’s much anticipated OS, that’s due in the first week of June has leaked ahead of its official launch time.

ISO files for an 8400 build of Windows 8 have been making their way to Chinese forums and torrent websites for the past 24 hours and many people have already confirmed successful installations. I’m curios how many of them were actually done on a tablet… This build brings updates Windows 8 Metro style apps, including new Sports, Travel and News applications. Microsoft also brings an updated boot screen, cursors and wallpapers for the Release Preview, plus a brand new version of Aero, but apparently that won’t make it to RTM, so don’t get cozy with it.

Desktop improvements for multiple monitors are also included in this build. Microsoft promised to launch the Release Preview of Win 8 in the first week of June, but no exact release date has been mentioned. The Chinese copy may be online now, but most of the users are waiting for the official English copy. Microsoft will hold a keynote at Computex on June 6th, that may mark the debut of the Windows 8 RP and some showcasing of new tablets.