A 2011 hacking attack of Google Inc.'s Gmail prompted Hillary Rodham Clinton and her top aides to worry about "antiquated" government-issued laptops and the security of private email accounts widely used by government officials.
Clinton's use of a private email account while she led the department now hangs over her campaign to become the Democratic nominee for the November 2016 presidential election.
The introspection is revealed in the latest batch of Clinton's emails released by the State Department, the fifth dump in a monthly series set to last until January 2016.