diff --git a/arangod/Aql/ExecutionEngine.cpp b/arangod/Aql/ExecutionEngine.cpp
index 52cb32926b..b7c10ebc9c 100644
--- a/arangod/Aql/ExecutionEngine.cpp
+++ b/arangod/Aql/ExecutionEngine.cpp
@@ -737,6 +737,10 @@ struct CoordinatorInstanciator : public WalkerWorker<ExecutionNode> {
           else {
             THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
           }
+
+          if (remoteNode == nullptr) {
+            THROW_ARANGO_EXCEPTION(TRI_ERROR_INTERNAL);
+          }
           
           auto&& shardIds = collection->shardIds();
 
diff --git a/arangod/GeoIndex/GeoIndex.cpp b/arangod/GeoIndex/GeoIndex.cpp
index 68f591c2e0..ce59c60eaf 100644
--- a/arangod/GeoIndex/GeoIndex.cpp
+++ b/arangod/GeoIndex/GeoIndex.cpp
@@ -907,7 +907,7 @@ void GeoResultsInsertPoint(GeoResults * gr, int slot, double snmd)
                 if(gr->snmd[jj1]>gr->snmd[jj2])
                 {
                     temp=jj1;
-                    jj1=jj2;
+                    // jj1=jj2;
                     jj2=temp;
                 }
                     /* so now jj2 is >= jj1 */
diff --git a/arangod/V8Server/ApplicationV8.cpp b/arangod/V8Server/ApplicationV8.cpp
index d07f36e2f1..a193e94620 100644
--- a/arangod/V8Server/ApplicationV8.cpp
+++ b/arangod/V8Server/ApplicationV8.cpp
@@ -568,7 +568,7 @@ void ApplicationV8::collectGarbage () {
   // can be performed more early for all dirty contexts. The flag is set
   // to false again once all contexts have been cleaned up and there is nothing
   // more to do
-  bool useReducedWait = false;
+  volatile bool useReducedWait = false;
 
   // the time we'll wait for a signal
   uint64_t const regularWaitTime = (uint64_t) (_gcFrequency * 1000.0 * 1000.0);
diff --git a/arangod/V8Server/V8Traverser.h b/arangod/V8Server/V8Traverser.h
index ecf82aa034..b19e8779f2 100644
--- a/arangod/V8Server/V8Traverser.h
+++ b/arangod/V8Server/V8Traverser.h
@@ -48,7 +48,7 @@ struct VertexId {
 
   VertexId () 
     : cid(0), 
-      key(nullptr) {
+      key("") {
   }
 
   VertexId (TRI_voc_cid_t cid, char const* key) 
diff --git a/arangod/Wal/Slots.cpp b/arangod/Wal/Slots.cpp
index e604bad747..8792a7ee71 100644
--- a/arangod/Wal/Slots.cpp
+++ b/arangod/Wal/Slots.cpp
@@ -158,7 +158,6 @@ SlotInfo Slots::nextUnused (uint32_t size) {
           CONDITION_LOCKER(guard, _condition);
           TRI_ASSERT(_waiting > 0);
           --_waiting;
-          hasWaited = false;
         }
 
         // cycle until we have a valid logfile
@@ -286,7 +285,6 @@ SlotInfo Slots::nextUnused (uint32_t size,
           CONDITION_LOCKER(guard, _condition);
           TRI_ASSERT(_waiting > 0);
           --_waiting;
-          hasWaited = false;
         }
 
         // cycle until we have a valid logfile
diff --git a/lib/Basics/AssocMulti.h b/lib/Basics/AssocMulti.h
index 03948bcf5b..68488b12af 100644
--- a/lib/Basics/AssocMulti.h
+++ b/lib/Basics/AssocMulti.h
@@ -1125,6 +1125,7 @@ namespace triagens {
           IndexType oldAlloc = b._nrAlloc;
 
           b._nrAlloc = static_cast<IndexType>(TRI_NearPrime(static_cast<uint64_t>(size)));
+
           try {
             b._table = new EntryType[b._nrAlloc];
 #ifdef __linux__
diff --git a/lib/Basics/AssocUnique.h b/lib/Basics/AssocUnique.h
index 8a592616e4..acc2e74cb1 100644
--- a/lib/Basics/AssocUnique.h
+++ b/lib/Basics/AssocUnique.h
@@ -236,6 +236,8 @@ namespace triagens {
 
             // This might throw, is catched outside
             b._table = new Element* [targetSize];
+            
+            b._nrAlloc = targetSize;
 
 #ifdef __linux__
             if (b._nrAlloc > 1000000) {
@@ -251,10 +253,9 @@ namespace triagens {
               b._table[i] = nullptr;
             }
 
-            b._nrAlloc = targetSize;
-
             if (b._nrUsed > 0) {
               uint64_t const n = b._nrAlloc;
+              TRI_ASSERT(n > 0);
 
               for (uint64_t j = 0; j < oldAlloc; j++) {
                 Element* element = oldTable[j];
diff --git a/lib/V8/v8-buffer.cpp b/lib/V8/v8-buffer.cpp
index 5237537e0f..e5b5813494 100644
--- a/lib/V8/v8-buffer.cpp
+++ b/lib/V8/v8-buffer.cpp
@@ -1166,6 +1166,10 @@ static void JS_Copy (const v8::FunctionCallbackInfo<v8::Value>& args) {
     TRI_V8_THROW_RANGE_ERROR("sourceEnd out of bounds");
   }
 
+  if (target_data == nullptr || source == nullptr || source->_data == nullptr) {
+    TRI_V8_THROW_EXCEPTION_MESSAGE(TRI_ERROR_INTERNAL, "invalid pointer value");
+  }
+
   size_t to_copy = MIN(MIN(source_end - source_start,
                            target_length - target_start),
                            source->_length - source_start);