Microsoft said the RC will be available for download by program developers and IT professionals subscribing to the MSDN and TechNet networks on April 30 and available more broadly on May 5.
The company has still not said when the finished version would begin to be installed on PCs or available to buy in shops, but the company's chief financial officer said on Thursday it could be as early as July.
That would allow Microsoft to capitalize on back-to-school sales and set it up for a strong holiday shopping season.
Microsoft's operating systems, installed on the vast majority of the world's PCs, are still the backbone of the company, providing more than half of its $4.4 billion profit last quarter.
