Windows 3.00a

Windows 3.00a is a minor update to Windows 3.00 released on 31 October 1990. It fixed a few bugs from the earlier release. Windows 3.0 with Multimedia Extensions 1.0 is based on this version.

A version of this build for the Intel Inboard 386/PC (an ISA card with a 386, 387 socket and some RAM intended for earlier systems), from 14 January 1991, was dumped by BitHistory on 16 September 2020 and uploaded to the Internet Archive on 4 December 2020.

Unlike the original English release, the Spanish version has a copyright date of 1991, implying that it was released later.

Quirks
Due to some changes introduced with bug fixes, Microsoft Virtual PC 2004/2007 users have to include the line  in  's   section.