diff --git a/src/OpenFOAM/global/argList/argList.C b/src/OpenFOAM/global/argList/argList.C
index 6873c7c15715bd2bedda80d87b585e8baf917eeb..01b68a32de4aaf63702308af3544a04609801292 100644
--- a/src/OpenFOAM/global/argList/argList.C
+++ b/src/OpenFOAM/global/argList/argList.C
@@ -673,6 +673,17 @@ void Foam::argList::parse
                     adjustOpt = true;
                     source = source/"decomposeParDict";
                 }
+
+                if
+                (
+                   !source.isAbsolute()
+                && !(source.size() && source[0] == '.')
+                )
+                {
+                    source = rootPath_/globalCase_/source;
+                    adjustOpt = true;
+                }
+
                 // Could also check for absolute path, but shouldn't be needed
                 if (adjustOpt)
                 {