Emailgate: In 2009 as she was sworn in as secretary of state, Hillary Clinton had a private server set up at her family home in New York that she could use to send emails away from her official state department account.
The use of a private server went against State Department rules and, as it was not secure, made her potentially vulnerable to hacking. Mrs Clinton was ordered to turn over the emails to the State Department but before doing so, she and her staff, deleted some 31,000 messages. An FBI investigation concluded that her actions were careless, but not criminal. However, 15,000 further emails discovered by investigators are due to be published before the election.
Paid speeches to Wall Street:
Both Donald Trump and former Democrat rival Bernie Sanders have accused her of being too closely connected to Wall Street.
A study of declared income shows that Mrs Clinton and her husband have made
$153?million (pounds 115?million) in speaking fees. She gave 92 speeches between 2013 and 2015. Her standard fee is $225,000, and she collected $21.6?million in just under two years. Her critics argue she cannot be impartial and is in hock to unpopular big banks.
Benghazi raids:
On Sept 11 2012, Islamist militants attacked a US diplomatic compound in Benghazi, Libya, leaving a US ambassador and three other Americans dead. It later emerged that the State Department, led at the time by Mrs Clinton, had rejected appeals for additional security at the consulate where the attack took place. Numerous inquiries tallying tens of millions of dollars concluded that Mrs Clinton had not been at fault. But for many Americans, it is all that they remember from her time as secretary of state.
Ghosts of the past: From Whitewater to Monica Lewinsky, for much of his presidency Bill Clinton was either under investigation or seemingly on the brink of being impeached. Older voters remember the constant news dramas, which seemed to distract the president from his job. Even with her name cleared by multiple investigations, many Americans regard Mrs Clinton as untrustworthy.