Clinton exclusively used a private server, and did not provide records until after leaving office. She did not comply with existing rules as understood by virtually everyone else. Classified information was exchanged over her private email system. She exclusively and unethically used a private email for company business.
Clinton's claim that '90 percent' of the emails are contained within the State Dept. system is fallacious at best, a bald-faced lie at worst, since she cannot make a definitive statement and certainly cannot attribute that to the Dept. If she did not have a private server, officials now would not be scrutinizing every single Clinton email for possible public release.
She has acted in an irresponsible manner, and should at the very LEAST be disqualified from the race.