Her ex-bosses at Meta (the parent company of Facebook) have threatened legal action if she does anything to promote the memoir.
She faces a fine of US$50,000 ($84,300) every time she speaks disparagingly about the company, The Daily Telegraph reported.
Meta warned that her planned appearance at the Hay Festival would breach the conditions.
She appeared on stage with investigative journalist Carole Cadwalladr and academic Tim Wu at the event, who wrote a book about Silicon Valley.
Introducing the panel, The Guardian reported that Cadwalladr said: “I think this might be a Hay first, in which we have an author in a hostage situation. Blink once if you can hear us, Sarah, twice if [Mark] Zuckerberg is an a**hole.”
Wu called the lawsuit a “machine reaction, not a personal vendetta”, BBC reported.
He accused Meta of “maximising the punishment” as a warning to any other would-be Meta whistleblowers and described the action as “censorship”.
Sarah Wynn-Williams, a former director at Facebook, has detailed allegations of misconduct and sexual harassment. Photo / Getty Images
“This is performative,” Cadwalladr said.
Meta told the BBC that claims they were trying to silence her “is not what’s happening here”.
“There is a binding interim arbitration award against Ms Wynn-Williams which she agreed to during her time at Meta and which explicitly prohibits her from promoting her book,” it said.
Helen Bagnall, Hay Festival’s programmes director, told the audience: “Since Sarah Wynn-Williams’s Meta exposé Careless People was published in March 2025, she has faced immense legal pressure. Today, on the advice of lawyers, she is unable to speak, but she joins us on stage”.
Wynn-Williams was the former global policy director for Facebook, now owned by founder Mark Zuckerberg’s parent company Meta, from 2011 to 2017.
Her book recounted her experiences working for the company, including accusations of sexual harassment by a long-time Facebook executive and claims the company explored breaking into the Chinese market by appeasing government censors there.
Meta won a court order barring Wynn-Williams from promoting Careless People: A Cautionary Tale of Power, Greed and Lost Idealism or from making derogatory statements about Facebook shortly after it was released.
At issue was whether her book breached what was believed to be anti-disparagement provisions in her severance agreement with the company.
In March 2025, an RNZ interview with Wynn-Williams was cancelled after Meta banned her from doing interviews about it.
Meta provided a statement to RNZ in which it called the book “a mix of out-of-date and previously reported claims about the company and false accusations about our executives”.
– RNZ