In the field of domestic service robots, recovery from faultsis crucial to promote user acceptance. In this context we focusin particular on some specific faults, which arise from theinteraction of a robot with its real world environment.Even a well-modelled robot may fail to perform its tasks successfullydue to unexpected situations, which occur while interacting.These situations occur as deviations of propertiesof the objects (manipulated by the robot) from their expectedvalues. Hence, they are experienced by the robot as externalfaults.In this paper we present two approaches to handle externalfaults which result from inadequate descriptions of a planneroperator. In both approaches we assume that the robot isable to detect the occurrence of the fault at the planning levelby monitoring the effects of an executed action. In our workwe limit the scope of the sources of external faults to naturalphysical phenomena. Hence, we do not consider casesin which an external agent (e.g. another robot, a human being)is the cause of a detected fault. We apply the proposedapproaches to scenarios in which the robot performs a manipulationtask (pick and place).