In learning to use software, people spend at least 30% of their time on dealing with errors. It could therefore be desirable to exploit users' errors rather than to avoid them. That is, to include error information in a manual to support users in dealing with errors. An experiment was performed to examine the functionality of such error information in a manual for a word processor. Two manuals were compared, one with error information and one from which this information was removed. Forty-two subjects were randomly assigned to one of the two conditions. Subjects who used the manual with error information were expected to become more proficient at using the word processor (i.e. to show better constructive and corrective skills) and to develop more self-confidence. The results were equivocal. On some aspects of skill the error information in the manual led to better performance (i.e. correcting syntactic errors). On others it had an adverse effect (i.e. detection of semantic errors and overall error-correction time). Explanations are advanced for these findings and topics for further research are identified.