This is key because Clinton, in her news conference on Tuesday to answer questions about why she exclusively used a private email address to communicate during her tenure, told reporters she'd thought her communications to senior department officials were always saved. That's an important point, given legal requirements for preserving federal records.
"In meeting the record-keeping obligations, it was my practice to email government officials on their State or dot-gov accounts so that the emails were immediately captured and preserved," she said.
The news about the State Department's archiving practices -- and the change that started in February -- could refuel the furor of Republicans over Clinton's choice to not use her government email account, to have a private server in her family home house her emails, and to decide (with her staff) which emails to delete and which to turn over to the State Department for review.
Rep. Susan Brooks, a member of the select committee investigating the 2012 Benghazi attack, said in the Republicans' weekly media address Saturday, "You see, right now there is no way for us to know whether we have all of the State Department communications that rightfully belong to the American people."
"The only way to truly know is by having access to Secretary Clinton's personal server," the Indiana Republican added. "We are asking Secretary Clinton to turn her server over to a neutral, third-party arbiter. After a complete inventory, this arbiter can make a determination as to which emails should be public and which should remain private. These decisions would be completely impartial and independent."
So far, Brooks' committee had gotten just under 300 of Clinton's emails from the State Department.
Last year, as it was trying to update its records, the State Department asked former secretaries of state for nonpersonal emails from their personal accounts that could be work-related.
That request prompted Clinton to turn over 30,490 emails -- about 55,000 pages. Clinton has asked for those emails to be made public, and department officials are reviewing them to make sure no sensitive information is released.
Clinton's office had said her account contained 62,320 sent and received emails from March 2009 to February 2013.
"About half were personal that were not in any way related to work. I had no reason to save them," Clinton said at her press conference.
The fact that all emails from senior officials weren't automatically saved until recently doesn't mean they are gone, according to the State Department.
"I wouldn't state it's lost to history, because there are always -- there are technical means of gaining access to past information," spokeswoman Jen Psaki said Friday.
At the same time, Psaki said the State Department chose to change its approach -- by automatically saving all emails -- "because it's an imperfect system."
"This is a more efficient and better way," she said of the new system. "But, obviously, there were ways to preserve (emails), and employees and individuals were expected to do that prior to this new process."
Separately, Psaki said that a letter was recently sent to former State Department staffers asking for their help in the preservation effort.
"If they should become aware ... of federal record in their possession -- such as an email sent or received on a personal email account while (they were) serving in their official capacity at the Department -- that ... record (should) be made available to the Department," Psaki said the ex-staffers were told.
Even before last month's chance, emails of current Secretary of State John Kerry, who uses a government address, were already being saved automatically.