Hillary not only stored AT LEAST 110 classified emails on her server, but she also used portable devices to discuss and send/received classified information.
Classified information doesn't become unclassified just because it lacks markings. She knew what was classified.
But no charges because she didn't "intend" to break the laws she did -- which is not an element of the NDA she signed. She was responsible for proper storage and protection of that information, and failure to do so intentionally OR THROUGH NEGLIGENCE is a serious national security breach and against the law.
She also failed to leave those emails and documents at the state department when she left. That's a major violation of the law -- theft of government documents.
She also is responsible for the destruction of 30,000+ files on her computers and the physical destruction of government devices such as tablets and cell phones.
No charges for willful destruction of government property and records.
The reason many of the emails and files are known to the FBI is because Anthony Weiner's laptop had COPIES of everything his wife -- Clinton's Chief of Staff -- sent and received. That constitutes unauthorized disclosure. Weiner did not have clearance to access state department communications.
Comey testified under oath that Clinton made many false statements to the FBI and the public about her emails and storage of classified.
No charges of obstructing the investigation or lying to the FBI.
If your name is Clinton or you are in their circle, the laws just don't apply.
If Hillary can skate on the "I didn't mean to" defense, so can Trump.
Almost every government official tied to this criminal activity was given immunity by the DOJ. Why? Immunity is a tool used to motivate someone to be a witness against someone else or to provide evidence to make a case against someone else. Immunity is never offered unless there is some benefit to the prosecution.
Since nobody was prosecuted, it sure looks like immunity was being offered to protect the players, not to help make a case against anyone.