diff --git a/src/finiteVolume/fields/fvPatchFields/derived/directMappedFixedValue/directMappedFixedValueFvPatchField.C b/src/finiteVolume/fields/fvPatchFields/derived/directMappedFixedValue/directMappedFixedValueFvPatchField.C
index 78a61ce472..f343967bc1 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/directMappedFixedValue/directMappedFixedValueFvPatchField.C
+++ b/src/finiteVolume/fields/fvPatchFields/derived/directMappedFixedValue/directMappedFixedValueFvPatchField.C
@@ -78,7 +78,7 @@ directMappedFixedValueFvPatchField<Type>::directMappedFixedValueFvPatchField
             << "\n    for patch " << p.name()
             << " of field " << this->dimensionedInternalField().name()
             << " in file " << this->dimensionedInternalField().objectPath()
-            << exit(FatalIOError);
+            << exit(FatalError);
     }
 }
 
@@ -111,7 +111,7 @@ directMappedFixedValueFvPatchField<Type>::directMappedFixedValueFvPatchField
             << "\n    for patch " << p.name()
             << " of field " << this->dimensionedInternalField().name()
             << " in file " << this->dimensionedInternalField().objectPath()
-            << exit(FatalIOError);
+            << exit(FatalError);
     }
 }
 
diff --git a/src/meshTools/directMapped/directMappedPolyPatch/directMappedPolyPatch.C b/src/meshTools/directMapped/directMappedPolyPatch/directMappedPolyPatch.C
index 808942c562..a5eb3f4cb0 100644
--- a/src/meshTools/directMapped/directMappedPolyPatch/directMappedPolyPatch.C
+++ b/src/meshTools/directMapped/directMappedPolyPatch/directMappedPolyPatch.C
@@ -199,6 +199,16 @@ void Foam::directMappedPolyPatch::calcMapping() const
             << "Mapping already calculated" << exit(FatalError);
     }
 
+    if (offset_ == vector::zero)
+    {
+        FatalErrorIn("directMappedPolyPatch::calcMapping() const")
+            << "Invalid offset " << offset_ << endl
+            << "Offset is the vector added to the patch face centres to"
+            << " find the cell supplying the data."
+            << exit(FatalError);
+    }
+
+
     // Get global list of all samples and the processor and face they come from.
     pointField samples;
     labelList patchFaceProcs;