diff --git a/arangod/Aql/ModificationBlocks.cpp b/arangod/Aql/ModificationBlocks.cpp
index 3fa2cb81bf..a44bdbd40e 100644
--- a/arangod/Aql/ModificationBlocks.cpp
+++ b/arangod/Aql/ModificationBlocks.cpp
@@ -588,6 +588,10 @@ AqlItemBlock* UpdateBlock::work(std::vector<AqlItemBlock*>& blocks) {
 
     VPackSlice toUpdate = object.slice();
 
+    if (toUpdate.isNone()) {
+      continue;
+    }
+
     // fetch old revision
     OperationResult opRes = _trx->update(_collection->name, toUpdate, options); 
     if (!isMultiple) {
@@ -649,6 +653,16 @@ AqlItemBlock* UpdateBlock::work(std::vector<AqlItemBlock*>& blocks) {
 UpsertBlock::UpsertBlock(ExecutionEngine* engine, UpsertNode const* ep)
     : ModificationBlock(engine, ep) {}
 
+bool UpsertBlock::isShardKeyError(VPackSlice const slice) const {
+  TRI_ASSERT(_isDBServer);
+
+  if (_usesDefaultSharding) {
+    return false;
+  }
+
+  return slice.hasKey(StaticStrings::KeyString);
+}
+
 /// @brief the actual work horse for inserting data
 AqlItemBlock* UpsertBlock::work(std::vector<AqlItemBlock*>& blocks) {
   size_t const count = countBlocksRows(blocks);
@@ -758,8 +772,12 @@ AqlItemBlock* UpsertBlock::work(std::vector<AqlItemBlock*>& blocks) {
         AqlValue const& insertDoc = res->getValueReference(i, insertRegisterId);
         VPackSlice toInsert = insertDoc.slice();
         if (toInsert.isObject()) {
-          insertBuilder.add(toInsert);
-          insRows.emplace_back(dstRow);
+          if (_isDBServer && isShardKeyError(toInsert)) {
+            errorCode = TRI_ERROR_CLUSTER_MUST_NOT_SPECIFY_KEY;
+          } else {
+            insertBuilder.add(toInsert);
+            insRows.emplace_back(dstRow);
+          }
         } else {
           errorCode = TRI_ERROR_ARANGO_DOCUMENT_TYPE_INVALID;
         }
@@ -983,6 +1001,10 @@ AqlItemBlock* ReplaceBlock::work(std::vector<AqlItemBlock*>& blocks) {
     }
 
     VPackSlice toUpdate = object.slice();
+
+    if (toUpdate.isNone()) {
+      continue;
+    }
     // fetch old revision
     OperationResult opRes = _trx->replace(_collection->name, toUpdate, options); 
     if (!isMultiple) {
diff --git a/arangod/Aql/ModificationBlocks.h b/arangod/Aql/ModificationBlocks.h
index 3e50259096..ceb6fb719f 100644
--- a/arangod/Aql/ModificationBlocks.h
+++ b/arangod/Aql/ModificationBlocks.h
@@ -126,6 +126,9 @@ class UpsertBlock : public ModificationBlock {
  protected:
   /// @brief the actual work horse for updating data
   AqlItemBlock* work(std::vector<AqlItemBlock*>&) override final;
+
+ private:
+  bool isShardKeyError(arangodb::velocypack::Slice const) const;
 };
 
 }  // namespace arangodb::aql