Windows Longhorn build 4089

Windows Longhorn build 4089 is an unleaked Milestone 7 build of Windows Longhorn.mTwo screenshots of this build have been leaked, one of which shows a prototype version of Windows Movie Maker based on Windows Presentation Foundation, the other shows a version of the Display Properties applet based on the aforementioned framework. The second screenshot was leaked on the BetaArchive Discord by ReflectiaX on 2020-01-26.

In the BetaArchive topic "New Longhorn builds for a new decade" by Grabberslasher on 2020-01-23 where more than 35 Longhorn pre and post-reset builds were leaked, including all then-unleaked builds showcased on UX.Unleaked, ReflectiaX mentioned that he once had a copy of this build, or at least another 4089 numbered build, but had since lost it.