Officials at the National Archives, who are in charge of telling the rest of the government how to save and safeguard e-mail, are red-faced about a mishap in the computers of their own high command.

They say they "lost" at least 43,000 electronic messages last summer, wiped out without a useful trace. They were supposed to have a backup system that could have replaced the missing information, but they said it was not working properly.

"All efforts to restore these messages failed," Deputy Archivist Lewis J. Bellardo said recently in response to an inquiry from author-researcher Scott Armstrong, a longtime critic of the agency's electronic record-keeping policies.

The e-mails, which included the internal messages of 125 users in the offices of Archivist John W. Carlin, Bellardo, the headquarters of the regional archives and five staff units, were erased sometime over the June 18-21 weekend. Officials could not say just how many messages, accumulated over a four-month period, were deleted, but "based on a conservative estimate of 300 messages for each account," Bellardo said, "we calculate that at least 43,000 messages were lost."

Officials say they still do not know just what caused the deletions. They say the audit log features that might have provided a clue had been turned off because they would have hampered the system's performance.

Making things worse, according to Assistant Archivist L. Reynolds Cahoon, was the fact that adequate backup procedures were not in place. "It's really distressing to us," Cahoon said. He said "it was our understanding that backups were being made," both on a daily basis and a periodic systemwide basis, but the agency's contractor, Signal Corp. of Fairfax, had been doing neither as the Archives had specified.

Cahoon said he did not want to blame Signal because "we should have been more vigilant about what our contractor was doing," but, in any case, he said Signal has replaced the project manager and the supervisor who was responsible for the backups.

Armstrong and another longtime critic of the Archives's e-mail policies, researcher Eddie Becker, were skeptical of the official explanations, especially Bellardo's assertion that "the deletion was unintentional rather than willful or malicious."

"Did someone hit the wrong button? Spill coffee? Did the system get hit by lightning?" Becker asked. "It sounds like they don't know what happened. Most likely it was some disgruntled person. The Archives can be like the Post Office. And for them to be managing other people's records when their own records are such a disaster is ludicrous."

"This was definitely not a bolt of lightning or a power surge," Cahoon said. He said the messages could have been accidentally erased by someone trying to delete a single user's messages and hitting the wrong key. He believes this is what happened. He said backup systems have been beefed up to guard against another mishap, but he said the safest way to save important messages is to print them out.

"We don't have a lot of trust in our systems at this point," Cahoon said. "We're using software that's used all over the world, but it's not foolproof yet. It's subject to human error."

Agency spokeswoman Susan Cooper said Carlin prints out all his important or "record" messages every day, as do other top officials. "We take this very seriously," she said of the erasures, "but at the end of the day, we don't think many 'record' messages were lost."

CAPTION: E-mails in Archivist John W. Carlin's office were among messages "lost."