Windows Me build 2470

Windows Me build 2470 is a pre-Beta 3 build of Windows Me. It requires a Beta ID during setup when upgrading and on boot, but it can be bypassed by terminating the "Inventory" task in the Task Manager.

Neptune reference
A file, namely, with the version number 5.50.5117.1 was found in this Millenium build, but it is unknown whether this Neptune build ever existed.

Some speculate this would've been a Milestone 2 build. It would've been compiled someday after 1999-12-11, meaning it would be one of the last Neptune builds before the Neptune project was canceled in 2000-01.