Windows 7 is already being used as a main operating system by millions of people.

Millions of people are already running Windows 7 full time, despite it only being released in beta form, Microsoft has said.

In a post on the official Windows 7 Engineering blog, the development team wrote: “We’ve also learned that many of you (millions) are running Windows 7 Beta full time.”

While the date of the next version, the Release Candidate (RC), is yet to be confirmed by Microsoft, it should arrive soon. The engineering team warned that testers should not upgrade straight from the beta to the RC, however, as it doesn’t mimic what “real-world” consumers would do and could lead to incompatibility issues. “We know that means reinstalling, recustomising, reconfiguring, and so on. That is a real pain.”

The team also stressed that upgrades should not go from Windows XP, but from Vista. “We realised at the start of this project that the ‘upgrade’ from XP would not be an experience we think would yield the best results.” This is because of changes in how drivers, hardware support and applets have been configured, meaning an XP to Windows 7 upgrade would “not be nearly as high quality as a clean install”.

“We do provide support for moving files and settings and will prompt at setup time, but applications will need to be reinstalled,” the team wrote. “We know that for a set of customers this trade-off seems less than perfect, but we think the upfront time is well worth it.”