All SequenceFlows leaving an ExclusiveGateway must have a guard, except for the default SequenceFlow.


An ExclusiveGateway acts as an ‘OR’, and therefore all the flows leaving from it should have a condition to satisfy in order to get the token, with the exception of the default flow, which gets the token if all conditions have failed.


If you have an ExclusiveGateway with outgoing flows which do not have a guard and which are not the default flow, you should edit the guard property of the flow.