Due to an editing error, the first and eighth paragraphs of the story "Dropbox left document storage accounts open for four hours," posted Tuesday, incorrectly identified the day on which Dropbox accidentally turned off password authentication. The incident occurred on Sunday.

The story has been corrected on the wire, and the corrected paragraphs now read:

Online storage service Dropbox accidentally turned off password authentication for its 25 million users for four hours on Sunday -- although "much less than 1 percent" of those accounts were accessed during the period, the company said. It is still investigating whether any of those accounts were improperly accessed.

Several Dropbox users were upset by Sunday's authentication problems, while others brushed it off.