From the LA Times link:
...Before documents are released, archives staff must read them and, by law, must redact material that they determine contains classified information, invades a person's privacy, reveals trade secrets, reveals confidential advice from presidential advisors or raises other concerns specified in the records law.
Asked how long it might be before Hillary Clinton's records are released, the library's chief archivist said it could take years.
"We're processing as fast as we can," Melissa Walker said.
Not fast enough, in the view of some who have been waiting. A conservative watchdog group called Judicial Watch filed suit against the National Archives last month, demanding the release of Hillary Clinton's diaries, telephone logs, daily planners and schedules. In the 1990s, the group filed suits against the Clinton administration that led to revelations about fundraising practices, including Democratic campaign donors being tapped for official trade missions. In the most recent suit, Judicial Watch said it had submitted its request more than a year ago and had received nothing, save for confirmation that the library possessed "a substantial volume" of such papers.
Staffing pressures have prevented the National Archives from keeping up with an expanding workload. In 2002, the agency employed 334 archivists. This year, the number is down to 301. That 10% drop came during a period when the National Archives assumed jurisdiction over two more presidential libraries: those of Clinton and Richard Nixon.
"If we have fewer trained personnel, we are unable to do as many preservation projects as we might like, and we're less able to serve the public in ways we would like to," said Susan Cooper, a spokeswoman for the National Archives.