diff --git a/lib/richlist/storage/mongo.js b/lib/richlist/storage/mongo.js
index c944d36..0999979 100644
--- a/lib/richlist/storage/mongo.js
+++ b/lib/richlist/storage/mongo.js
@@ -191,13 +191,22 @@ class MongoStorage {
             }
         }
 
+        const insertManyCollection = (collection, data) => {
+            if(data.length === 0) {
+                return Promise.resolve()
+            }
+            // insertMany fails when data is empty array 
+            // (node:1) UnhandledPromiseRejectionWarning: MongoError: Invalid Operation, no operations specified
+            return collection.insertMany(data)
+        }
+
         // insert documents
-        return this.transactions.insertMany(txs.map(tx => ({
+        return insertManyCollection(this.transactions, txs.map(tx => ({
             hash: tx.hash,
             locktime: tx.locktime,
             version: tx.version
         }))).then(() => {
-            return this.outputs.insertMany(outputs);
+            return insertManyCollection(this.outputs, outputs);
         }).then(() => this.blocks.insertOne({
             hash: block.hash,
             height: block.height,