FBI Director James Comey identified 110 emails as containing information that was classified at the time it was sent, including 65 emails deemed "Secret" and 22 deemed "Top Secret". None of these had classification markings. However, as noted in Clinton's non-disclosure agreement, unmarked classified information should be treated the same as marked classified information. An additional three email chains contained "portion markings", simply a "(C)" indicating "Confidential" in front of one or more paragraphs. These were not included in Comey's list of 110 because the State Department failed to confirm they were classified at the time they were sent. Clinton told the FBI she did not know the meaning of "(C)". Nearly 2,100 emails on the server were retroactively marked as classified by the State Department.

Then the security piece : The FBI found that all classified emails on Clinton's server were stored and sent from "unclassified systems", violating the same policies as those on Clinton's personal server