How well informed are you?

Regarding Hillary Clinton's emails some of which were said to contain classified information, not one of the emails in question had a classified header on it.

FBI Director James Comey confirmed that none of the Clinton emails purported to have classified information in it, had a classified header on it.

FBI Director, James Comey confirmed that Clinton spoke truthfully when she said she did not sent/receive anything marked classified in her personal email account.

Colin Powell, Secretary of State in the George W. Bush administration had a personal email account and conducted official Government business via this account.

FBI Director James Comey admitted that given that none of the Clinton emails, purported to contain classfied information, had a classified header on it, it was a reasonable inference for Sec. Clinton to make that the emails did not contain classified information.

Of the "Clinton" emails, purported to contain classified information, none were initiated by Sec. Clinton. They were all sent to or forwarded to her.

Personal email accounts like the ones used by Colin Powell and Condi Rice when they served as Secretary of State, with commercial email service providers, can be examined by cyber-security personnel of the email service providers.

Nobody can guarantee that classified information in email accounts with commercial email service providers, has not been compromised nor seen by non Government personnel who do not possessing Government Security clearances.

Classified information was found in Colin Powell's and Condi Rice's emails.