Many contemporary software products have subsystems for automatic crash reporting. However, it is well-known that the same bug can produce slightly different reports. To manage this problem, reports are usually grouped, often manually by developers. Manual triaging, however, becomes infeasible for products that have large userbases, which is the reason for many different approaches to automating this task. Moreover, it is important to improve quality of triaging due to a large volume of reports that needs to be processed properly. Therefore, even a relatively small improvement could play a significant role in the overall accuracy of report bucketing. The majority of existing studies use some kind of a stack trace similarity metric, either based on information retrieval techniques or string matching methods. However, it should be stressed that the quality of triaging is still insufficient. In this paper, we describe TraceSim-a novel approach to this problem which combines TF-IDF, Levenshtein distance, and machine learning to construct a similarity metric. Our metric has been implemented inside an industrial-grade report triaging system. The evaluation on a manually labeled dataset shows significantly better results compared to baseline approaches.