Windows Vista build 5219 (winmain idx02.050830-2010)

Windows Vista build 5219 is a pre-Beta 2 build of Windows Vista. This build was the first post-reset build that leaked that had the sidebar but it had to be downloaded separately. This was among the earliest builds to use the Windows Vista logo within the About Windows dialog box, with a slight gradient and slightly flamboyant green background, and a wholly white Windows flag logo, along with Windows text of the same tone of color, as opposed to the old Windows Longhorn logo used from the 4044 (unleaked) and 4051 (leaked) builds up to at least as far as build 5212, if not even later.

Also, Aero Glass was updated in this build, live taskbar thumbnails were introduced, as well as taskbar transparency (in pre-reset, the Sidebar enabled a new taskbar, which was transparent with DWM enabled, however, without Sidebar the taskbar was still opaque), not to mention that this build was evenly distributed among 2005 PDC (Professional Developers Conference) attendants on 2005-09-13, having also been released to Microsoft beta testers and MSDN (Microsoft Developer Network) subscribers).

This was also the first known build in which an Ultimate variant of it was compiled, not to mention that it also included Super Fetch. As said above, the Windows Sidebar, much to the surprise of everyone, was reimplemented by the time this build was compiled, despite being notably absent in the earlier builds compiled after the reset occurred.

This build was also among the first to introduce a new version of Windows Media Center, codenamed "Diamond".

Despite Microsoft's decision to later remove WinFS from Windows Vista, certain people testing this build noted that WinFS was still implemented in this build, misleading people to believe that it was still to be released as part of Windows Vista upon the RTM, though there were no visible processes for WinFS.

There is also an earlier version of this build compiled on 2005-08-24, but it is unleaked.