diff --git a/src/OpenFOAM/db/IOobject/IOobject.C b/src/OpenFOAM/db/IOobject/IOobject.C
index f6c5facb39a7236ca3b6fc454265349e40f12b39..1df9ffa68754d5fb0bdf2bf3ac40a94325f28b24 100644
--- a/src/OpenFOAM/db/IOobject/IOobject.C
+++ b/src/OpenFOAM/db/IOobject/IOobject.C
@@ -72,6 +72,8 @@ bool Foam::IOobject::IOobject::fileNameComponents
         return false;
     }
 
+    string::size_type first = path.find('/');
+
     if (first == string::npos)
     {
         // no '/' found - no instance or local