Microsoft’s Build 2015 conference, which runs from April 29 through May 1 in San Francisco, has a singular purpose: Sell independent developers on the concept of Windows 10, due later this year. The stakes couldn’t be higher. Windows 8, the previous OS version, failed to ignite the imaginations of developers or consumers; according to data from Net Applications, it continues to lag in market-share behind not only Windows 7, but also the ancient Windows XP. If Windows 10 likewise meets an anemic response, it could spell serious trouble for the Windows franchise, which remains a central pillar of Microsoft’s business. The key to avoiding that anemic response, in turn, is convincing developers that Windows remains an exciting platform, despite the increasing importance of mobile operating systems such as Android and iOS. If developers build tens of thousands of interesting apps for Windows, it could help Microsoft seize some of the initiative back from Google and Apple, which currently dominate the consumer-computing space. Microsoft has other initiatives in the works, of course. There’s the HoloLens, an augmented-reality headset that could prove a hit with the right applications. Speaking of applications, the company will use this year’s Build conference to continue pushing “universal apps,” which (in theory) will work across both PC and mobile platforms. And in a break from longtime tradition, Microsoft continues to port key productivity apps onto rival platforms, including iOS and Android. All those initiatives are designed to show that Microsoft remains relevant in a rapidly evolving technology arena. But if Windows 10 isn’t a blockbuster, the company will have a harder time convincing shareholders and customers that its best days aren’t behind it. Image: Microsoft