diff --git a/src/Base/Quantity.cpp b/src/Base/Quantity.cpp
index 446e0dd555..918956f043 100644
--- a/src/Base/Quantity.cpp
+++ b/src/Base/Quantity.cpp
@@ -96,7 +96,7 @@ Quantity::Quantity(double value, const QString& unit)
         this->_Unit = tmpQty.getUnit();
         this->_Value = value * tmpQty.getValue();
     }
-    catch (const Base::Exception&) {
+    catch (const Base::ParserError&) {
         this->_Value = 0.0;
         this->_Unit = Unit();
     }
diff --git a/src/Base/QuantityPyImp.cpp b/src/Base/QuantityPyImp.cpp
index ccfce27c12..7da2c1b199 100644
--- a/src/Base/QuantityPyImp.cpp
+++ b/src/Base/QuantityPyImp.cpp
@@ -131,7 +131,7 @@ int QuantityPy::PyInit(PyObject* args, PyObject* /*kwd*/)
         try {
             *self = Quantity::parse(qstr);
         }
-        catch(const Base::Exception& e) {
+        catch(const Base::ParserError& e) {
             PyErr_SetString(PyExc_ValueError, e.what());
             return -1;
         }
@@ -146,7 +146,7 @@ int QuantityPy::PyInit(PyObject* args, PyObject* /*kwd*/)
         try {
             *self = Quantity(f, unit);
         }
-        catch(const Base::Exception& e) {
+        catch(const Base::ParserError& e) {
             PyErr_SetString(PyExc_ValueError, e.what());
             return -1;
         }
diff --git a/src/Base/Unit.cpp b/src/Base/Unit.cpp
index f2e0786288..d13c464927 100644
--- a/src/Base/Unit.cpp
+++ b/src/Base/Unit.cpp
@@ -107,7 +107,7 @@ Unit::Unit(const QString& expr)
     try {
         *this = Quantity::parse(expr).getUnit();
     }
-    catch (...) {
+    catch (const Base::ParserError&) {
         Sig.Length                   = 0;
         Sig.Mass                     = 0;
         Sig.Time                     = 0;
diff --git a/src/Base/UnitPyImp.cpp b/src/Base/UnitPyImp.cpp
index de20be1ce1..063168c1c7 100644
--- a/src/Base/UnitPyImp.cpp
+++ b/src/Base/UnitPyImp.cpp
@@ -90,8 +90,8 @@ int UnitPy::PyInit(PyObject* args, PyObject* /*kwd*/)
             *self = Quantity::parse(qstr).getUnit();
             return 0;
         }
-        catch (const Base::Exception& e) {
-            PyErr_SetString(PyExc_RuntimeError, e.what());
+        catch (const Base::ParserError& e) {
+            PyErr_SetString(PyExc_ValueError, e.what());
             return -1;
         }
     }
diff --git a/src/Base/UnitsApiPy.cpp b/src/Base/UnitsApiPy.cpp
index e1a5fd1708..103a7b9c1b 100644
--- a/src/Base/UnitsApiPy.cpp
+++ b/src/Base/UnitsApiPy.cpp
@@ -154,13 +154,9 @@ PyObject* UnitsApi::sParseQuantity(PyObject * /*self*/, PyObject *args)
     try {
         rtn = Quantity::parse(qstr);
     }
-    catch (const Base::Exception&) {
-        PyErr_Format(PyExc_IOError, "invalid unit expression \n");
-        return 0L;
-    }
-    catch (const std::exception&) {
-        PyErr_Format(PyExc_IOError, "invalid unit expression \n");
-        return 0L;
+    catch (const Base::ParserError&) {
+        PyErr_Format(PyExc_ValueError, "invalid unit expression \n");
+        return nullptr;
     }
 
     return new QuantityPy(new Quantity(rtn));
diff --git a/src/Gui/QuantitySpinBox.cpp b/src/Gui/QuantitySpinBox.cpp
index 91d1e497df..d40f0f02b0 100644
--- a/src/Gui/QuantitySpinBox.cpp
+++ b/src/Gui/QuantitySpinBox.cpp
@@ -150,7 +150,7 @@ public:
             value = result.getValue();
             return true;
         }
-        catch (Base::Exception&) {
+        catch (Base::ParserError&) {
             return false;
         }
     }
@@ -631,7 +631,7 @@ void QuantitySpinBox::setUnitText(const QString& str)
         Base::Quantity quant = Base::Quantity::parse(str);
         setUnit(quant.getUnit());
     }
-    catch (const Base::Exception&) {
+    catch (const Base::ParserError&) {
     }
 }