diff --git a/applications/utilities/mesh/manipulation/mergeMeshes/mergePolyMesh.C b/applications/utilities/mesh/manipulation/mergeMeshes/mergePolyMesh.C
index 7a114c3e22..69ae41748f 100644
--- a/applications/utilities/mesh/manipulation/mergeMeshes/mergePolyMesh.C
+++ b/applications/utilities/mesh/manipulation/mergeMeshes/mergePolyMesh.C
@@ -2,7 +2,7 @@
   =========                 |
   \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
    \\    /   O peration     |
-    \\  /    A nd           | Copyright (C) 2011-2016 OpenFOAM Foundation
+    \\  /    A nd           | Copyright (C) 2011-2017 OpenFOAM Foundation
      \\/     M anipulation  | Copyright (C) 2016 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
@@ -36,7 +36,7 @@ License
 
 namespace Foam
 {
-defineTypeNameAndDebug(mergePolyMesh, 1);
+    defineTypeNameAndDebug(mergePolyMesh, 1);
 }
 
 
@@ -442,7 +442,6 @@ void Foam::mergePolyMesh::addMesh(const polyMesh& m)
                 )
             );
     }
-
 }
 
 
@@ -474,7 +473,9 @@ void Foam::mergePolyMesh::merge()
         Info<< "Adding new patches. " << endl;
 
         label endOfLastPatch =
-            oldPatches[patchi - 1].start() + oldPatches[patchi - 1].size();
+            patchi == 0
+          ? 0
+          : oldPatches[patchi - 1].start() + oldPatches[patchi - 1].size();
 
         for (; patchi < patchNames_.size(); patchi++)
         {