Microsoft's top Windows executive today said that the company will ship an almost-complete version of Windows 8 the first week of June.
Stephen Sinofsky, president of the Windows and Windows Live division, announced the timing Tuesday at a developers event in Tokyo, according to a Twitter message by the company.
Although Microsoft has traditionally dubbed such milestones "release candidate," or RC, to describe nearly-finished software, the Windows 8 build will be labeled "Release Preview," a nod to the naming of the earlier editions, Developer Preview and Consumer Preview.
Microsoft shipped Windows 8 Consumer Preview on Feb. 29.
The early June timeframe is in sync with earlier speculation, including claims made last month by a Dutch blog, and with a mock schedule laid out by Michael Cherry, an analyst with Directions on Microsoft.
In March, Cherry said that Microsoft would deliver a release candidate three months after the Consumer Preview, with a "release to manufacturing," or RTM, edition three months after the RC.
According to Cherry's calendar, Microsoft had to deliver Windows 8 RC by the end of May and RTM by the end of August. RTM is the more important of the two yardsticks, as it notes the point at which code is offered to device manufacturers for prepping new PCs, to third-party developers for final testing of application compatibility and to peripheral vendors priming hardware designed for the OS.
Microsoft will need to accelerate Windows 8's timetable to make the late October launch date most experts believe is in the cards. But the early June debut of the Release Preview means Windows 8 remains about four weeks behind the pace of Windows 7.
In 2009, Windows 7 reached RC in early May and made RTM in late July before launching Oct. 22.
To make the crucial holiday sales season, Microsoft would have to offer Windows 8 no later than the end of October. Missing the mark would put Windows 8 at risk of repeating the problem-plagued Windows Vista, which got off to a bad start when it fell behind schedule and didn't ship until January 2007.
Vista is now generally regarded as one of Microsoft's rare operating system failures.
Microsoft has not disclosed an on-sale date for Windows 8 or discussed pricing, but last week it did unveil the three versions it will offer, including two for retail and pre-loading on new PCs, and one limited to enterprises that subscribe to Software Assurance.
Windows 8 Release Preview will be available to the public for downloading free of charge, Microsoft has previously promised.
Windows 7's RC went public on May 5, 2009, the first Tuesday of that month. If Microsoft uses the same day of the week for Windows 8, it would ship the Release Preview on Tuesday, June 5.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed . His email address is firstname.lastname@example.org.