The Free Software Foundation has embarked on a campaign to highlight its position that Microsoft’s Windows 8 operating system is a faulty product that restricts user freedom, invades user privacy, and controls user data.

Microsoft on Oct. 25 officially launched Windows 8 in New York City—and the Free Software Foundation showed up to crash the party. The FSF, a nonprofit, is dedicated to the philosophical idea that proprietary software is harmful to computer users’ freedoms. Microsoft declined to comment on the FSF’s campaign regarding Windows 8.

At the Windows 8 launch, the FSF talked to attendees about three potential dangers of Microsoft’s proprietary operating system. First, Windows 8 is proprietary software that is, according to the FSF, designed to control you as a user. You can’t modify Windows 8 or see how it is built, which means Microsoft can use its operating system to exploit users.

“Our biggest problem with Windows 8 is something pretty fundamental, which is that it’s a proprietary operating system,” said Libby Reinish, FSF’s campaign manager. “That, in and of itself, is going to restrict users’ freedom because you can’t see the source code, you can’t modify it and you can’t distribute it. We suspect that there’s a lot going on in that closed-source, proprietary code that could also be a privacy and security risk for users of Windows 8.”

Second, the FSF thinks that Windows 8 invades users’ privacy. It said Windows 8 includes software that inspects the contents of users’ hard drives, and that Microsoft claims the right to do this without warning. These programs have names such as “Windows Genuine Advantage,” according to the FSF.

And third, the FSF said that Windows 8 exposes users’ personal data. It said Windows 8 has a contacts cache that it said may store sensitive personal data and make users vulnerable to identity theft.

While at the Windows 8 launch, the FSF distributed DVDs loaded with Trisquel, a free software distribution of the GNU/Linux operating system. It was part of the FSF’s desire to encourage people who might be thinking about installing Windows 8 to join the free software movement instead.

“With the launch of Windows 8, a lot of people might feel like they have no choice but to ‘upgrade,’ but we want people to know that they do have a choice,” Reinish said. “There are a lot of free-software operating systems out there that will respect your freedom, that won’t record your personal data, and that won’t make money off compulsory upgrades.”

In an attempt to try to cut through what it said is just Microsoft’s marketing hype, the FSF’s anti-Windows 8 campaign will continue to track the proprietary operating system over the coming months to identify and explain the problems within it. As one of the first legs of its campaign, the FSF is inviting users to sign an online pledge on its website to not upgrade their computers to Windows 8 but to GNU/Linux instead.

“We’re just at the beginning of this campaign. We’re starting with this pledge, asking people not to switch to Windows 8,” Reinish said. “We’re going to support anyone who signs the pledge to make the switch to free software. We’ll provide them with resources and help them answer any questions that they have along the way.”