Windows Vista build 5221 (vbl ux dev checkin gamesux)

Windows Vista build 5221 (vbl_ux_dev_checkin_gamesux) is a pre-Beta 2 build of Windows Vista. This build was used as concept art in one of Microsoft's presentations and demos at PDC 2005. An image of this art was accidentally posted to Microsoft's website where WinBeta.pl archived it before it was taken down.

Alongside the facts, it has a very early compilation date way before other authentic Vista builds, and features a buildtag never seen before.

Unfortunately, the demo that originally showed this build was taken down and no archived versions exist at this time.

This is the earliest known build to include the start menu used in builds 5252 and afterwards, along with the start orb and taskbar seen in other vbl ux dev checkin builds.