Windows 3.1 build 068

Windows 3.1.068 is mentioned in an internal Microsoft document from 1992-02. It is also listed in a French Microsoft Knowledge Base article.

The document only says this build was released to testers on 1992-01-24.

The KB article describes an issue when Word for Windows 6.0 is started on this build - a general protection fault (GPF) is encountered in. This issues also happens on builds 70 and 71 and potentially other builds from the 0xx range according to the article.

According to Andrew Schulman's article titled Examining the Windows AARD Detection Code from 1993-09-01, this build contained the infamous AARD code (build 61 is also said to contain it) and was labeled as "pre-release build 3.10.068" and dated 1992-01-21. The real copy was not leaked until 2017-11-24 on BetaArchive.

Fake copy
A heavily modified copy of this build originated from betaguy224 and was later leaked by Battler. It was eventually declared to be fake, with files from the real build 68 mixed into other builds, and was removed from the BetaArchive FTP in 2013-07. It is still widely available online.