Windows Neptune build 5022.1

There are 29 files with version number 5.50.5022.1 and product name Microsoft(R) Neptune (TM) Operating System in Windows Millennium build 2332.2, but it is unknown whether this Neptune build ever existed.

Some speculate it would probably be one of the earliest Neptune builds, therefore part of the Milestone 1 stage. Judging by the file dates, it would be compiled someday before 1999-06-13. Coincidently, summer of 1999 is also when the Antitrust documents begin mentioning Neptune more frequently.