diff --git a/src/storm-pomdp/analysis/MemlessStrategySearchQualitative.cpp b/src/storm-pomdp/analysis/MemlessStrategySearchQualitative.cpp
index 6552071ef..5326cacf5 100644
--- a/src/storm-pomdp/analysis/MemlessStrategySearchQualitative.cpp
+++ b/src/storm-pomdp/analysis/MemlessStrategySearchQualitative.cpp
@@ -75,11 +75,10 @@ namespace storm {
                 nrStatesPerObservation.push_back(states.size());
             }
             winningRegion = WinningRegion(nrStatesPerObservation);
-            if(options.validateEveryStep) {
+            if(options.validateResult || options.validateEveryStep) {
                 STORM_LOG_WARN("The validator should only be created when the option is set.");
                 validator = std::make_shared<WinningRegionQueryInterface<ValueType>>(pomdp, winningRegion);
             }
-
         }
 
         template <typename ValueType>
@@ -638,14 +637,13 @@ namespace storm {
                     }
 
                 }
-                // TODO temporarily switched off due to intiialization issues when restartin.
                 STORM_LOG_ASSERT(!updated.empty(), "The strategy should be new in at least one place");
                 if(options.computeDebugOutput()) {
                     winningRegion.print();
                 }
                 if(options.validateEveryStep) {
                     STORM_LOG_WARN("Validating every step, for debug purposes only!");
-                    validator->validate();
+                    validator->validate(surelyReachSinkStates);
                 }
                 stats.updateNewStrategySolverTime.start();
                 for(uint64_t observation : updated) {
@@ -686,6 +684,12 @@ namespace storm {
 
                 STORM_LOG_INFO("... after iteration " << stats.getIterations() << " so far " << stats.getChecks() << " checks." );
             }
+            if(options.validateResult) {
+                STORM_LOG_WARN("Validating result is a winning region, only for debugging purposes.");
+                validator->validate(surelyReachSinkStates);
+                STORM_LOG_WARN("Validating result is a maximal winning region, only for debugging purposes.");
+                validator->validateIsMaximal(surelyReachSinkStates);
+            }
             winningRegion.print();
 
             if (!allOfTheseStates.empty()) {
diff --git a/src/storm-pomdp/analysis/WinningRegion.h b/src/storm-pomdp/analysis/WinningRegion.h
index 7b95fed85..aaf51d839 100644
--- a/src/storm-pomdp/analysis/WinningRegion.h
+++ b/src/storm-pomdp/analysis/WinningRegion.h
@@ -11,6 +11,11 @@ namespace storm {
 
             bool update(uint64_t observation, storm::storage::BitVector const& winning);
             bool query(uint64_t observation, storm::storage::BitVector const& currently) const;
+            bool isWinning(uint64_t observation, uint64_t offset) const {
+                storm::storage::BitVector currently(observationSizes[observation]);
+                currently.set(offset);
+                return query(observation,currently);
+            }
 
             std::vector<storm::storage::BitVector> const& getWinningSetsPerObservation(uint64_t observation) const;
 
diff --git a/src/storm-pomdp/analysis/WinningRegionQueryInterface.cpp b/src/storm-pomdp/analysis/WinningRegionQueryInterface.cpp
index 167a09e26..79db31a74 100644
--- a/src/storm-pomdp/analysis/WinningRegionQueryInterface.cpp
+++ b/src/storm-pomdp/analysis/WinningRegionQueryInterface.cpp
@@ -1,3 +1,4 @@
+#include <storm/exceptions/UnexpectedException.h>
 #include "storm/storage/expressions/Expression.h"
 #include "storm-pomdp/analysis/WinningRegionQueryInterface.h"
 
@@ -39,6 +40,7 @@ namespace storm {
 
         template<typename ValueType>
         bool WinningRegionQueryInterface<ValueType>::staysInWinningRegion(storm::storage::BitVector const& currentBeliefSupport, uint64_t actionIndex) const {
+            STORM_LOG_ASSERT(currentBeliefSupport.getNumberOfSetBits() > 0, "One cannot think one is literally nowhere");
             std::map<uint32_t, storm::storage::BitVector> successors;
             STORM_LOG_DEBUG("Stays in winning region? (" << currentBeliefSupport << ", " << actionIndex << ")");
             for (uint64_t oldState : currentBeliefSupport) {
@@ -57,17 +59,17 @@ namespace storm {
             for (auto const& entry : successors) {
 
                 if(!isInWinningRegion(entry.second)) {
-                    STORM_LOG_DEBUG("Belief support " << entry.second << " is not winning");
+                    STORM_LOG_DEBUG("Belief support " << entry.second << " (obs " << entry.first << ") is not winning");
                     return false;
                 } else {
-                    STORM_LOG_DEBUG("Belief support " << entry.second << " is winning");
+                    STORM_LOG_DEBUG("Belief support " << entry.second << " (obs " << entry.first << ") is winning");
                 }
             }
             return true;
         }
 
         template<typename ValueType>
-        void WinningRegionQueryInterface<ValueType>::validate() const {
+        void WinningRegionQueryInterface<ValueType>::validate(storm::storage::BitVector const& badStates) const {
             for (uint64_t obs = 0; obs < pomdp.getNrObservations(); ++obs) {
                 for(auto const& winningBelief : winningRegion.getWinningSetsPerObservation(obs))   {
                     storm::storage::BitVector states(pomdp.getNumberOfStates());
@@ -81,7 +83,63 @@ namespace storm {
                             break;
                         }
                     }
-                    STORM_LOG_ASSERT(safeActionExists, "Observation " << obs << " with associated states: " << statesPerObservation[obs] << " , support " << states);
+                    STORM_LOG_THROW(safeActionExists, storm::exceptions::UnexpectedException, "Observation " << obs << " , support " << states);
+                }
+            }
+        }
+
+        template<typename ValueType>
+        void WinningRegionQueryInterface<ValueType>::validateIsMaximal(storm::storage::BitVector const& badStates) const {
+            for (uint64_t obs = 0; obs < pomdp.getNrObservations(); ++obs) {
+                STORM_LOG_DEBUG("Check listed belief supports for observation " << obs << " are maximal");
+                for(auto const& winningBelief : winningRegion.getWinningSetsPerObservation(obs))   {
+                    storm::storage::BitVector remainders = ~winningBelief;
+                    for(auto const& additional : remainders) {
+                        uint64_t addState = statesPerObservation[obs][additional];
+                        if (badStates.get(addState)) {
+                            continue;
+                        }
+
+                        storm::storage::BitVector states(pomdp.getNumberOfStates());
+                        for (uint64_t offset : winningBelief) {
+                            states.set(statesPerObservation[obs][offset]);
+                        }
+                        states.set(statesPerObservation[obs][additional]);
+                        assert(states.getNumberOfSetBits() == winningBelief.getNumberOfSetBits() + 1);
+
+                        bool safeActionExists = false;
+                        for(uint64_t actionIndex = 0; actionIndex <  pomdp.getTransitionMatrix().getRowGroupSize(statesPerObservation[obs][0]); ++actionIndex) {
+                            if (staysInWinningRegion(states,actionIndex)) {
+                                STORM_LOG_DEBUG("Action " << actionIndex << " from " << states << " is safe. ");
+                                safeActionExists = true;
+                                break;
+                            }
+                        }
+
+                        STORM_LOG_THROW(!safeActionExists,storm::exceptions::UnexpectedException, "Observation " << obs << ", support " << states);
+                    }
+                }
+                STORM_LOG_DEBUG("All listed belief supports for observation " << obs << " are maximal. Continue with single states.");
+
+                for (uint64_t offset = 0; offset < statesPerObservation[obs].size(); ++offset) {
+                    if(winningRegion.isWinning(obs,offset))  {
+                        continue;
+                    }
+                    uint64_t addState = statesPerObservation[obs][offset];
+                    if(badStates.get(addState)) {
+                        continue;
+                    }
+                    storm::storage::BitVector states(pomdp.getNumberOfStates());
+                    states.set(addState);
+                    bool safeActionExists = false;
+                    for(uint64_t actionIndex = 0; actionIndex <  pomdp.getTransitionMatrix().getRowGroupSize(statesPerObservation[obs][0]); ++actionIndex) {
+                        if (staysInWinningRegion(states,actionIndex)) {
+                            safeActionExists = true;
+                            break;
+                        }
+                    }
+
+                    STORM_LOG_THROW(!safeActionExists, storm::exceptions::UnexpectedException, "Observation " << obs << "  , support " << states);
                 }
             }
         }
diff --git a/src/storm-pomdp/analysis/WinningRegionQueryInterface.h b/src/storm-pomdp/analysis/WinningRegionQueryInterface.h
index 44b9cc53e..3ccf45478 100644
--- a/src/storm-pomdp/analysis/WinningRegionQueryInterface.h
+++ b/src/storm-pomdp/analysis/WinningRegionQueryInterface.h
@@ -14,7 +14,9 @@ namespace storm {
 
             bool staysInWinningRegion(storm::storage::BitVector const& beliefSupport, uint64_t actionIndex) const;
 
-            void validate() const;
+            void validate(storm::storage::BitVector const& badStates) const;
+
+            void validateIsMaximal(storm::storage::BitVector const& badStates) const;
         private:
             storm::models::sparse::Pomdp<ValueType> const& pomdp;
             WinningRegion const& winningRegion;