Windows Vista build 5212 (vbl ux dev checkin)

Windows Vista build 5212 (vbl_ux_dev_checkin) is an unleaked pre-Beta 2 build of Windows Vista. This build was shown at PDC 2005, showcasing the Digital Locker. Microsoft had released the screenshot of this build showing the taskbar (thus also showing the build tag). Sometime later, the taskbar was cropped from the screenshot, along with the build tag. However, ActiveWin managed to reupload the screenshot prior to it being replaced.

This build notably features a new Start button that has been changed to an orb, similar to how the "Start" text was absent in x86 pre-reset Longhorn builds with the Slate theme if the sidebar was enabled. This orb would not make it into the main branch until 5252 however. The orb is a lot darker than the one seen in builds 5252 to RTM and the taskbar is different than previous and later builds with the exception of the  compiles of build 5221 and 5203.