Paying tribute to her,one friend described Karen as ‘a strong businesswoman who had an air of authority about her’,while another said she ‘didn’t have any enemies’ (Picture: Handout)

One staff member was killed and several people were injured in the attack.

'It's the noise before the chaos, the noise that is always there when I close my eyes to sleep.'

Sam Altman’s OpenAI has become one of the world’s most influential tech companies (Picture: Justin Sullivan/Getty Images)

'With only a few words you can prompt a whole song.'

Thousands of US users are also experiencing problems.