Methods and systems receive printing symptoms from a user into a graphic user interface and receive system information from a printing device exhibiting the printing symptoms. The method analyzes the printing symptoms using a diagnostic inference system operating on a computerized device operatively connected to the graphic user interface to produce candidate component defects. The method outputs diagnostic recommendations containing the candidate component defects to the user. The diagnostic recommendations include at least one representative image of a printing defect corresponding to each candidate component defect, and probabilities of correctness of the candidate component defects displayed alongside the representative image.