Windows Longhorn build 4017

Windows Longhorn build 4017 is a Milestone 5 build of Windows Longhorn. On 2020-01-23, this build was listed on a thread by Grabberslasher, founder of the UX.Unleaked blog, to be released to the BetaArchive FTP, and was released as the first two builds of 33 other Longhorn builds the next day, alongside build 4029 (Lab06 n). This build shares a lot of similarities with build 4015 (main), including a working Desktop Composition Engine that isn't different to build 4015.