Initial judgments related to key decisions in software projects are often based on one-sided or misleading information. The initial assessment of the benefits of introducing a new development tool may for example be based a vendor's sales demonstration or a reference client's favorable description. In this paper we study software professionals' abilities to adjust their early, biased judgments when receiving contradicting or less biased information. The first study, involving 160 software professionals, found a strong under-adjustment for the impact of misleading information and one-sided argument. A follow-up two weeks later found that this under-adjustment was not removed over time. The second study, involving 65 software professionals, found that the ability to update biased judgments may sometimes be quite good, but that it is hard to predict when. A practical consequence of our results is that software professionals should strongly emphasize the avoidance of biased and potentially misleading information and not trust that they are able to adjust their judgments and beliefs when more reliable and unbiased information are available.