A Microsoft partner build of Windows Blue that appears to be build 9364 has leaked to the internet today, the first publicly available leaked build of Windows since well before the launch of Windows 8. The build, believed to be of Windows Blue Milestone 1, has only been leaked in the 32-bit edition as a 2.63 GB ISO, and with a partial filename of 9364.0.FBL_PARTNER_OUT13.130315-2105_X86FRE_CLIENT it appears to be sourced from France.

Checks on the setup.exe within the download have confirmed that at least part of the ISO is legitimate, however the slow three-part download means that we haven't been able to fully verify the contents of this build. A screenshot has been leaked accompanying the release of the build to the web, which shows a full build string including the unique employee ID which will no doubt land some people in hot water.