SAN FRANCISCO — Microsoft appears to believe that the next version of its operating system is such a big change that it’s calling the software Windows 10, skipping the more logical Windows 9.
But compared with Windows 8, its much-maligned predecessor, the rough sketch of Windows 10 that Microsoft showed for the first time this week will seem comfortingly familiar to many.
The changes reflect Microsoft’s continued search for a formula that will reinvigorate Windows and, along with it, sales of PCs, which have flagged badly in recent years. While Microsoft has lost a lot of cachet to Apple, Google and other companies that shape the mobile market, Windows still runs most PCs.
With Windows 8, Microsoft redesigned its operating system for a world increasingly populated with touch-screen devices, creating a start screen that looked unlike any Windows desktop before it. It filled the screen with a grid of tiles that allowed users to open applications with the tap of a finger and to see a constant flow of photos, Facebook updates and emails.
But the new interface was deeply polarizing among users and seemed to overlook the fact that most people still use Windows on devices with a mouse and keyboard, not a touch screen.
“We didn’t quite get it right,” Joe Belfiore, a corporate vice president in Microsoft’s operating systems group, said at the company’s event Tuesday.
Although Microsoft is not getting rid of the start screen with Windows 10, it is tucking it away so that many users may never see it. The software borrows some elements of the tile interface, but they will pop up on the screen only when a user clicks a menu button at the bottom of the screen.
The main screen of Windows 10 uses the desktop interface that Microsoft has used for decades. Microsoft began making it easier for its users to get rid of the tile interface with updates to Windows 8, but the new software goes further.
“This is what Windows 8 should have been,” said Carolina Milanesi, chief of research with Kantar Worldpanel ComTech, a consumer research group.
Microsoft executives emphasized that the company was not giving up on making touch an important part of Windows. If someone uses Windows 10 on a hybrid device with a keyboard and a touch screen — Microsoft’s Surface is one example — the software will reformat itself with the tile interface when a keyboard is detached. Some analysts predict that eventually most PCs will incorporate touch screens.
Despite the familiar look, Microsoft executives said skipping the Windows 9 name was justified by other ambitious changes in the software. The operating system now shares a lot of code with other Microsoft products, including its smartphone operating system, which will let developers more easily create apps that work across different devices.
Microsoft said it planned to brief big business customers on the changes. Those customers represent Microsoft’s most dependable source of profit, and they have largely ignored Windows 8.
According to a study by Forrester Research, only about 1 in 5 organizations offers Windows 8 on PCs to employees. Many businesses run Windows 7, which came out about four years ago.
David K. Johnson, a Forrester analyst, said, “Microsoft needs to give enterprises reasons to move to a new version before it becomes a crisis.”
With Windows 10, Microsoft wants to give business customers the opportunity to provide input on the software before it is finished, said Terry Myerson, executive vice president of Microsoft’s operating system group. The product will not be released in final form until the latter half of next year.
“It’s a little bit of a journey,” Myerson said. “We decided to jump off today before we had all the answers.”