diff --git a/RhSolutions.AddIn/Tools/MergeTool.cs b/RhSolutions.AddIn/Tools/MergeTool.cs
index 504b607..62d7e73 100644
--- a/RhSolutions.AddIn/Tools/MergeTool.cs
+++ b/RhSolutions.AddIn/Tools/MergeTool.cs
@@ -17,9 +17,12 @@ internal class MergeTool : Tool
     {
         IFileDialog dialog = RhSolutionsAddIn.ServiceProvider.GetRequiredService<IFileDialog>();
         string[] files = dialog.GetFiles();
-        _reader = _readerFactory.GetReader("Excel");
-        var products = _reader.ReadProducts(files);
-        _writer = _writerFactory.GetWriter("NewPrice");
-        _writer.WriteProducts(products);
+        if (files.Length > 0)
+        {
+            _reader = _readerFactory.GetReader("Excel");
+            var products = _reader.ReadProducts(files);
+            _writer = _writerFactory.GetWriter("NewPrice");
+            _writer.WriteProducts(products);
+        }
     }
 }