A lot is resting on the new OS after its predecessor Windows 8 was heavily criticized. However, mobile app developers are unconvinced that Windows 10 will be worth their time, given Windows' tiny market share in the OS smartphone space.
"Nobody is asking for a Windows app and that's due to the market size alone," Andreas Rasmussen, managing partner at mobile development company Nodes, told CNBC by phone.
According to market research company IDC, Windows owns 3.2 percent of the OS market share for smartphones, compared to 79.4 percent for Android and 16.4 percent for iOS.
As a result developers can find it difficult to monetize their products.
"A challenge is that the Windows app ecosystem is less mature than other platforms, so some of the ways that we generate revenue are more difficult," Mike Newman, founder of Big Duck Games, the studio behind the popular FlowFree game, told CNBC by phone.
"For example, there are fewer ad networks supporting Windows and also fewer advertisers promoting other apps and games, so our ad space is less valuable."
Mobile struggles 'worrisome'
Microsoft's problems in the mobile space appear to be worsening.
Earlier this month, the U.S. tech giant announced plans to cut up to 7,800 jobs and take a $7.6 billion writedown on the devices business it bought from Nokia for $7.5 billion last year.
At the same time, it's over a year since Microsoft released a flagship smartphone. This is causing concern among some developers, even those already developing for Windows.
"It is worrisome. If their market isn't growing or isn't there, and if Microsoft won't support it anymore, it's a market to stay away from," said Peter de Jong, co-founder of Codeglue, the company behind popular mobile game Rocket Riot, which is available on Windows 8.
Microsoft has recognized its past problems and changed strategy with Windows 10. The Redmond, WA-based company is offering Windows 10 as a free upgrade to Windows 7, Windows 8.1 and Windows Phone 8.1 customers, to tempt more users onto the platform.
In addition, there are two key features of Windows 10 aimed at attracting more developers.
The first is called "Universal Apps," which should let developers write one code to work across different types of devices, like mobiles and PCs, with minimal tweaks.
De Jong said this feature wasn't as easy to use as Microsoft made out, but the majority of developers CNBC spoke to said it would save time as there was no need to write completely different pieces of code for different devices.
"Our latest game, Mars Pop, is our first universal app and, thanks to this feature, we were able to save a lot of time in the development stage since it's available on both Windows and Windows Phone platforms at once," Outfit7, the maker of the "My Talking Tom" app told CNBC in a statement.
The second feature unveiled by Microsoft was a tool to make it easier for Google Android and Apple iOS developers to make their apps available for Windows phones as well.
Normally, developers would have to write separate codes for rival mobile OS.
Like Universal Apps, developers have welcomed this move from Microsoft.
"That's really interesting, and may make it much easier for us to bring new apps and app updates to Windows in the future," Big Duck Games' Newman told CNBC.