Windows 8.1 build 9431

Windows 8.1 build 9431 is the official Preview build of Windows 8.1, also known as the Milestone Preview. This build was released on June 26, 2013 with the occasion of the Build 2013 conference taking place. At the time of its release, it was possible to upgrade to this build from a Windows 8 copy by using the Windows Store or by downloading an ISO from TechNet or MSDN. The ISOs were made publicly available the day after, on June 27, 2013 in multiple languages, when the day 2 keynote started. An ARM version of the build was also available, but it was only obtainable through the Microsoft Store. OOBE in this build is also the same as the RTM.

User interface
This is the first build to bring back the visible Start button after being absent since Windows 8 build 8186.

SkyDrive
This build's SkyDrive client has several notable registry entries. Apart from the previous SkyDrivePagesTest value (which work in all avaliable builds), eight other registry values exist in this build. This makes the complete list look like this: HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\CameraRollDisabled HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\DisabledState HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\IsDomainAiccount HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\SkyDriveTest HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\MSAInterruptState HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\TotalSize HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\DisabledState HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\OtherSize HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\BackupSize HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\FileSize HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\SkyDrivePagesTest\ErrorState This version also includes a HKCU\Software\Microsoft\Windows\CurrentVersion\SkyDriveOptIn key with two values: Brand & OptIn choice, implying that there were plans for a SkyDrive subscription service at the time of this build. Setting Brand to 1 will cause the SkyDrive app to rebrand itself as Microsoft Drive, which showed the possibility of a name change (a result of the then recent BSkyB vs SkyDrive lawsuit; the new name produced from the suit ended up being OneDrive).

Legacy F12 tools
If you want to get the old F12 tools back, just create or change these two DWORD's in the registry to 1: HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\EnableLegacyF12 HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\FlipF12Shortcut

Media Center
You can get Media Center in this build. To get it, just copy this key: MBFBV-W3DP2-2MVKN-PJCQD-KKTF7 (from Windows 8 Release Preview) to the Add features dialog.