Softpedia reports that a build of Windows 8 Release Preview has already been leaked and now resides on various peer to peer websites in the form of an ISO image. It's Build 8400 and arrives just a week or more before Microsoft reportedly unleashes Windows 8 Release Preview to the public sometime early June (supposedly Friday).
The leaked beta OS is reportedly a legit build of Release Preview for China. The ISO can be verified by looking at its HASH which should read as follows:
MD5: F3AC28467258EC9F0ECEAF9690A0F06E
SHA1: C21B69413E08FCFB756EEDB2B99D0C0472486D1C
CRC32: 67F85067
This leak likely stems from the early release for OEM partners or those who have access to the Technology Adoption Program (TAP). While also Build 8400, this version weighs at a meaty 2.43 GB and features a build string of 8400.0.WINMAIN_WIN8RC.120518-1423. It also has a different HASH as follows:
MD5: 7285DA50A07E33BC3B5A20E48AFAF375
SHA-1: 8BED436F0959E7120A44BF7C29FF0AA962BDEFC9
CRC32: 70B0ACEA
As the name states, this build is a simple taste of what's to come in the retail release later this year. Compared to the Consumer Preview launched back in February, this build will reportedly feature a cleaner and modified user interface. The Aero Glass interface will be taking a hike after serving on two operating systems, and the usability and performance of the platform will be enhanced compared to the Consumer Preview.
A recent screenshot taken from Windows 8 Release Preview revealed a few new apps including Sports, News and Travel, allowing users to see the content in Metro. So far it's unknown whether these apps will ship with the Release to Manufacturing version of Windows 8 given that many users may not be into sports or travel.
The screenshot also revealed that other apps have received a visual update. All Windows LIVE based apps now have a unique color so that users can quickly pinpoint what apps and services they want to use. The actual Windows LIVE brand is expected to be tossed out the window before Windows 8 RTM is released.