The conflict that flared up with renewed vigor in Nagorno-Karabakh in September - November 2020 demonstrated, how unstable “frozen conflicts” can be. The conflict also showed the insufficient ability of the traditional players in the region to prevent the hot phase of the conflict: the attention of NATO and EU was distracted by the coronavirus crisis, and Russian Federation initially took a rather restrained position, having an aim of maintaining the status of an arbitrator, not a spokesman for one of the parties. Azerbaijan's success in serious changes of status quo creates a dangerous precedent, the experience of which can be used by other states, while it is hardly possible to think of a real possibility not to repeat the Nagorno-Karabakh scenario due to the systematic nature of the reasons that led to the aggravation of the conflict. In the report Nagorno-Karabakh conflict is also observed from the standpoint of various theoretical approaches, the authors analyse the reasons of the last exacerbation and the likelihood of a similar development of events in other “frozen conflicts”. Based on the data on the key factors that are the reasons for the “unfreezing” of such conflicts, it is proposed to make a rating of “frozen conflicts” taking into account the likelihood of destabilization of the situation around them in the future.