Windows Neptune build 5099.1

There are 2 files, namely  and , with version number 5.50.5099.1 in Windows Millennium build 2419, but it is unknown whether this Neptune build ever existed.

Some speculate this could be a late Milestone 1 or an early Milestone 2 build. Judging by the file dates, it would have been compiled before 1999-11-17.