She was hacked and didn't report it.
She stated she did not want to use secure emails because her personal emails would be accessible.
The mens rea for multiple crimes just appeared in the State Department IG report.
http://www.washingtontimes.com/news/2016/may/25/hillary-clinton-failed-report-several-hacking-atte/
After one of the 2011 hack attempts
Mrs. Clinton’s tech staffer shut the server down for a few minutes, hoping that would solve the situation, but quickly warned top aides not to send
Mrs. Clinton “anything sensitive” after the attempted breach, according to the report, which was obtained by The Washington Times.
After another suspicious attempt
Mrs. Clinton said she was scared to open email — but failed to report the matter.
“Notification is required when a user suspects compromise of, among other things, a personally owned device containing personally identifiable information,” the investigators said. “However, OIG found no evidence that the Secretary or her staff reported these incidents to computer security personnel or anyone else within the Department.”
At one point in 2010,
Mrs. Clinton’s emails were ending up in subordinates’ spam filters because they were coming from a non-state.gov account. One of her top aides urged her to sign up for an official account or letting everyone in the department know of her address so she could be added as a verified account, but she refused, saying she didn’t “want any risk of the personal being accessible.