The lobby group is facing claims of misconduct, including an alleged rape at the CBI summer party in 2019.
Dame Carolyn Fairbairn - the CBI director general between 2015 and 2020 - told the Sunday Times she was not told of a sexual assault at the event.
Instead she was informed there was poor behaviour and staff drank too much.
Dame Carolyn told the newspaper: "There was no sit-down meal. With hindsight, I think that was a real mistake.
"We immediately decided not to allow this kind of format again."
She said previous CBI staff events were formal sit-down dinners with a seating plan. The CBI declined to comment. The BBC has made numerous attempts to contact Dame Carolyn.
The UK's biggest business lobby group is currently fighting for survival following a succession of damaging misconduct allegations, including two separate rape claims.
The assaults are being investigated by the City of London Police.
Following a review by Fox Williams, a law firm, the CBI the admitted that it "failed to filter out culturally toxic people during the hiring process".
CBI president Brian McBride also said: "Our systems of culture management, harm prevention and eradication were insufficient. Individually, some - though not all - of these organisational deficiencies may even seem small.
"But, together, they compounded to cause great harm to some of our own people, and then to the CBI as a whole."
However, Dame Carolyn - who was the CBI's first female director general since it was founded in 1963 - said she disagreed that there was a toxic culture at the organisation that allowed alleged misconduct to occur.
"This is about men behaving badly towards women," she told the newspaper. "I do not accept this connection between the culture of the organisation that I created and the actions of an individual who committed [an alleged] crime."
She said: "One of the issues I also have with this line of reasoning is that it seems to somehow justify the behaviour potentially of a man who committed [an alleged] crime."
Dame Carolyn was director general when John Allan - the outgoing chairman of Tesco - made an inappropriate comment to a CBI employee at its annual conference in late 2019.
Mr Allan, who was president of the CBI between 2018 and 2020, commented on a female staff member's clothing and said it suited her figure.
Dame Carolyn - who is set to join Tesco's board as a non-executive director in September - said: "I did not see his comment as sexualised but rather as a clumsy and insensitive attempt at a compliment by a man from an older generation."
She said that as soon as she was aware of the incident, she texted the female employee before confronting Mr Allan the next day on "how demeaning and really inappropriate it was".
Mr Allan has previously said that he was "mortified after making the comment" and "immediately apologised".
"The person concerned agreed the matter was closed and no further action was taken," said a spokesman for Mr Allan.
He has been accused of three other incidents of inappropriate conduct, including allegedly touching a female staff member at Tesco's annual shareholder meeting last year.
Mr Allan said the three claims are "utterly baseless".
Tesco said it had conducted a full investigation into the allegation concerning its employee, including reviewing video footage of the annual meeting.
The supermarket group said it had made "no findings of wrongdoing".
Nevertheless, on Friday it asked Mr Allan to step down early as its chairman, stating: "These allegations risk becoming a distraction to Tesco."
Mr Allan, who will leave in June after eight years in the role, said: "It is with regret that I am having to prematurely stand down from my position as chair of Tesco following the anonymous and unsubstantiated allegations made against me as reported by the Guardian."
He added: "There is no evidence of any wrongdoing at that time or at any stage of my chairmanship at Tesco and I remain determined to prove my innocence."
The CBI, which lobbies the government on behalf of 190,000 businesses, put "all policy and membership activity" on hold in April after swathes of companies either cancelled or suspended their membership following a number of reports in the Guardian.
Staff and firms will be asked to decide on the focus and the future of the CBI at an extraordinary general meeting in June.
The CBI is now being led by Rain Newton-Smith, its former chief economist, and she recently appointed a chief people officer to implement 35 recommendations that were identified from Fox Williams' review.