diff --git a/src/Mod/Sketcher/App/PropertyConstraintList.h b/src/Mod/Sketcher/App/PropertyConstraintList.h
index 931a99d0e..97a4f9b62 100644
--- a/src/Mod/Sketcher/App/PropertyConstraintList.h
+++ b/src/Mod/Sketcher/App/PropertyConstraintList.h
@@ -101,6 +101,9 @@ public:
     bool scanGeometry(const std::vector<Part::Geometry *> &GeoList) const;
     bool isGeometryInvalid(){return invalidGeometry;}
 
+    /// Return status of geometry for better error reporting
+    bool hasInvalidGeometry() const { return invalidGeometry; }
+
 
     const Constraint *getConstraint(const App::ObjectIdentifier &path) const;
     virtual void setPathValue(const App::ObjectIdentifier & path, const boost::any & value);
diff --git a/src/Mod/Sketcher/App/SketchObject.cpp b/src/Mod/Sketcher/App/SketchObject.cpp
index 1d2373e99..a96d83e2e 100644
--- a/src/Mod/Sketcher/App/SketchObject.cpp
+++ b/src/Mod/Sketcher/App/SketchObject.cpp
@@ -268,6 +268,8 @@ int SketchObject::solve(bool updateGeoAfterSolving/*=true*/)
 int SketchObject::setDatum(int ConstrId, double Datum)
 {
     // set the changed value for the constraint
+    if (this->Constraints.hasInvalidGeometry())
+        return -6;
     const std::vector<Constraint *> &vals = this->Constraints.getValues();
     if (ConstrId < 0 || ConstrId >= int(vals.size()))
         return -1;
diff --git a/src/Mod/Sketcher/App/SketchObjectPyImp.cpp b/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
index 55009ac0f..06cef9eae 100644
--- a/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
+++ b/src/Mod/Sketcher/App/SketchObjectPyImp.cpp
@@ -540,6 +540,8 @@ PyObject* SketchObjectPy::setDatum(PyObject *args)
             str << "Negative datum values are not valid for the constraint with index " << Index;
         else if (err == -5)
             str << "Zero is not a valid datum for the constraint with index " << Index;
+        else if (err == -6)
+            str << "Cannot set the datum because of invalid geometry";
         else
             str << "Unexpected problem at setting datum " << (const char*)Quantity.getUserString().toUtf8() << " for the constraint with index " << Index;
         PyErr_SetString(PyExc_ValueError, str.str().c_str());