Windows Longhorn build 4040

Windows Longhorn build 4040 is a Milestone 6 build of Windows Longhorn and is one of the last builds for that milestone. Grabberslasher first gave the details of this build on his UX.Unleaked blog. On 2020-01-23, this build was listed on a BetaArchive thread by the aforementioned user to be released to its FTP, and was released on 2020-01-31, alongside build 4002 and build 5356. This build is one of the last builds to include the Plex theme, together with the main compile of 4042.

Overall, this build has a very similar feature set to builds 4038 and 4039. Much of the interface remains similar to that of build 4038 due to Lab04's use of older code, likely from the main lab builds.