Techniques are provided for isolating faults in a software program by providing at least two code paths that are capable of performing the same operation. When a fault occurs while the one of the code paths is being used to perform an operation, data that indicates the circumstances under which the fault occurred is stored. For example, a fault-recording mechanism may store data that indicates the entities that were involved in the failed operation. Because they were involved in an operation that experienced a fault, one or more of those entities may be “quarantined”. When subsequent requests arrive to perform the operation, a check may be performed to determine whether the requested operation involves any of the quarantined entities. If the requested operation involves a quarantined entity, a different code path is used to perform the operation, rather than the code path from which the entity is quarantined.