Windows 3.1 build 043e

Windows 3.1 build 043e is the official Beta Release 2 of Windows 3.1. Until it was leaked on BetaArchive in February 2014, it was commonly believed to be a typo of build 034e, itself a mislabel of build 034f, which was already leaked. This build has an early tutorial and Reversi has been removed and replaced by Minesweeper.

It is also mentioned by internal Microsoft e-mails from late August 1991, as well as build 061d's  file.

Another e-mail from late December 1991 discusses sending "WFP SDK 1.0 Alpha (Kanji version)" and "WIN3.1 Beta2 (Kj)" to IBM Japan. It is unclear whether Beta 2 refers to this build (suggesting there is a Japanese version of it as well) or some other build from the Beta 2 stage.