This study describes a content analysis of reference transcripts taken from the NCknows virtual reference service. The analysis was performed to determine why the librarians consider some questions to be unanswerable at the time that they are submitted by users. Transcripts were coded by a classification of question causes, by how complete the reference interview was during the transaction, and then according to the reasons given for ending the chat early. The analysis showed that most reference interviews were incomplete and that the most common explanation for why the questions could not be answered at the time was that the librarians were already busy assisting other users. The study indicates that more North Carolina librarians should be hired to staff the service and that librarians should make a greater effort to conduct a complete reference interview so that more questions can be answered while the user is still online
