People frequently use information and communication technologies such as cell phones and email to mediate the transfer of private information. Often, this information is intended to be shared only with the recipient or recipients, and, in turn, kept from everyone else. However, people sometimes make errors when disclosing private information. These errors can occur when the intended information is sent to an unintended person or persons, when unintended information is sent to the intended person, or a combination of both. Fifteen adults (aged 19-23) were interviewed using the critical incident method to elicit past instances of erroneous disclosure. The interviewer sought to understand the circumstances surrounding incidents of erroneous relays of private information. Participants reported an average of 3.67 (SD = 1.59) instances of erroneous disclosure, or misclosure per person. Most reported errors involved email and other familiar technologies, with various designed-based causes. These findings point towards specific design features common to many information and communication technologies such as predictive text and button proximity that may lead to erroneous disclosure.