Windows 8.1 build 9403

Windows 8.1 build 9403 is an unleaked build of Windows 8.1. According to news sources from that time, it was released to partners on around 2013-05-27.

Supposedly development of most of the metro apps bundled with Windows 8.1 was already finished at that point and Microsoft was waiting for feedback to fix any bugs before getting the public preview ready.