SAN FRANCISCO (NYTIMES) — Facebook has been fighting for months the perception that it did not do enough to protect people’s privacy. On Thursday (June 7), the company said it had again failed to keep the information of millions of users private.

As many as 14 million Facebook users who thought they were creating private posts last month that only a small group of friends could see were, in fact, making public posts that anyone could view.

Facebook blamed a software bug for the problem. The company did not say how it had found the bug, or how it knew the problem was limited to 14 million people.

In a statement, Facebook said the bug affected users from May 18 to May 22, while the company was testing a new feature. By May 27, the company had changed the affected posts from a public setting back to a private one.

“We’d like to apologize for this mistake,” Erin Egan, Facebook’s chief privacy officer, said in a statement. “We have fixed this issue, and starting today we are letting everyone affected know and are asking them to review any posts they made during that time.”

In the last few months, Facebook executives have repeatedly been forced to apologise to users for failing to protect their privacy.

In March, The New York Times reported that the data of over 87 million people had been collected by Cambridge Analytica, a political firm with ties to the Trump campaign.

This week, The Times reported that Facebook had given cellphone makers, including Apple, Samsung and the Chinese firm Huawei, access to data on Facebook users and their friends. Members of Congress are now questioning Facebook and other tech companies about their relationship to Huawei.

Trust in Facebook has fallen by 66 per cent as a result of news stories in recent months, according to a survey by the Ponemon Institute, an independent research firm specialising in privacy and data protection.

Norman Sadeh, co-director of Carnegie Mellon University’s Privacy Engineering Program, said that although Facebook survived temporary losses of trust from the public in the past, the recent scandals appeared to be taking their toll on the social media company.

In response to the problems, the company has added a number of new privacy controls, as well as a centralized page for privacy and security settings. Sadeh said the new settings were still confusing.

One of Facebook’s key privacy features is that it lets people decide an audience for their posts. Someone can, for example, share a post with only a limited group of family and friends, or decide to make a post public so that anyone, including people not logged on to Facebook, can see it.

It was unclear if users could have done anything to their settings to prevent being affected by the bug the company revealed on Thursday.

Until Facebook and other companies improve their approach to privacy and develop settings that are easier to use and more aligned with what users want, “people should probably refrain from sharing too much sensitive information with these platforms,” Sadeh said.