The wireless mesh network (WMN), a key technology for next-generation wireless networking, represents a new type of wireless backbone network that supports stable communications to many mobile stations. The use of multiple channels and multiple interfaces is considered a viable method to secure sufficient network capacity. However, as WMN testbeds have been continually deployed in actual use, an interface failure problem has frequently appeared because most mesh nodes are exposed to the elements. A failure of the interface frustrates the algorithms for multi-channel and multi-interface use and, moreover, seriously hampers WMN connectivity. The present paper proposes interface failure tolerant algorithms which maintain not only WMN connectivity but multi-channel algorithms using a surviving interface. Detailed performance evaluations show the degree of failure mitigation using the proposed tolerance algorithms and provide a guideline for the active conditions of defective mesh nodes.