Microsoft said Tuesday it will make changes to Windows 8 later this year after a lukewarm reception for the dominant PC operating system released late last year.

Windows chief marketing officer Tami Reller said the company has sold more than 100 million licenses for Windows 8 but that Microsoft was planning an update called Windows Blue after listening to customers.

"Windows Blue is a code name for an update that will be available later this year, building on the bold vision set forward with Windows 8 to deliver the next generation of tablets and PCs," she said in a blog post.

"It will deliver the latest new innovations across an increasingly broad array of form factors of all sizes, display, battery life and performance, while creating new opportunities for our ecosystem."

She added that Windows Blue "is also an opportunity for us to respond to the customer feedback that we've been closely listening to since the launch of Windows 8 and Windows RT."

Some analysts say Microsoft was forced to act because of slow adoption of Windows 8, which made some radical changes to the design of the desktop.

"Blue is designed to address the reasons behind slow Windows 8 adoption in business and motivate the lagging Windows XP users to update before a massive successful cyber-attack or other disaster impacts that aging base," said analyst Rob Enderle at the Enderle Group.

"Blue will likely be the most important service release that Microsoft has ever made as a result."

With Windows 8, Microsoft was trying to create a system that could be used on mobile touchscreen devices while also serving the users of traditional PCs.

"It was too innovative, too quickly and customers pushed back," said independent analyst Jeff Kagan.

"This is Microsoft's new Diet Coke story. Companies who want to innovate must do so more slowly to be successful... I don't think Microsoft fully understands yet all the changes they need to make. I have several suggestions. Then again so do many others."

Stephen Baker at NPD group said Microsoft is correctly moving to a more frequent update cycle, which is needed in the fast-paced sector.

"They've come around to what is now kind of best practice around operating systems, an significant update and upgrade every year, like what competitors like Google and Apple do," Baker told AFP.

"Creating operating systems and not doing significant management for years probably doesn't work in today's environment."

Carolina Milanesi, analyst at Gartner, said the Windows 8 sales number is "not a great figure" and that by offering the same system for touch and non-touch devices confused consumers.

"They need more efforts on the ecosystem -- lower prices and more devices -- so that consumers really have a choice," she said.

While some PC users lamented the loss of the "start" button on Windows 8, Milanesi said it would be a mistake for Microsoft to turn the clock back: "It would be a failure" if the start button returned, she said.

Commenting on the lukewarm response to Windows 8, Reller said the new operating system "is a big, ambitious change."

"While we realize that change takes time, we feel good about the progress since launch, including what we've been able to accomplish with the ecosystem and customer reaction to the new PCs and tablets that are available now or will soon come to market," she added.

Microsoft launched Windows 8 last October, revamping its flagship system in an effort to make inroads in the fast-growing mobile segment. At the same time, it launched its Surface tablet computer.

Windows, the first version of which was launched in the 1990s, remains the dominant PC platform with some 90 percent of the world market. But in the mobile world, it is struggling against Apple's iOS and Google's Android system.

The company sold a modest 900,000 of its Surface tablets in the first quarter, according to research firm IDC.