diff --git a/src/Mod/Spreadsheet/App/Cell.cpp b/src/Mod/Spreadsheet/App/Cell.cpp
index 031cf0fba..4daa1068e 100644
--- a/src/Mod/Spreadsheet/App/Cell.cpp
+++ b/src/Mod/Spreadsheet/App/Cell.cpp
@@ -235,7 +235,7 @@ void Cell::setContent(const char * value)
                     if (expr)
                         delete expr->eval();
                 }
-                catch (Base::Exception & e) {
+                catch (Base::Exception &) {
                     expr = new StringExpression(owner->sheet(), value);
                 }
             }
diff --git a/src/Mod/Spreadsheet/App/Expression.cpp b/src/Mod/Spreadsheet/App/Expression.cpp
index bdd590f9c..19960bb11 100644
--- a/src/Mod/Spreadsheet/App/Expression.cpp
+++ b/src/Mod/Spreadsheet/App/Expression.cpp
@@ -60,6 +60,10 @@
 # define DOUBLE_MIN 2.2250738585072014E-308    /* min decimal value of a "double"*/
 #endif
 
+#if defined(_MSC_VER)
+#define strtoll _strtoi64
+#endif
+
 using namespace Base;
 using namespace App;
 using namespace Spreadsheet;
diff --git a/src/Mod/Spreadsheet/App/PreCompiled.h b/src/Mod/Spreadsheet/App/PreCompiled.h
index bae4d0bfe..767e0fca1 100644
--- a/src/Mod/Spreadsheet/App/PreCompiled.h
+++ b/src/Mod/Spreadsheet/App/PreCompiled.h
@@ -33,14 +33,16 @@
 # define SpreadsheetExport
 #endif
 
-#ifdef _PreComp_
 /// here get the warnings of to long specifieres disabled (needed for VC6)
 #ifdef _MSC_VER
-#	pragma warning( disable : 4251 )
-#	pragma warning( disable : 4503 )
-#	pragma warning( disable : 4786 )  // specifier longer then 255 chars
+#   pragma warning( disable : 4251 )
+#   pragma warning( disable : 4275 )
+#   pragma warning( disable : 4503 )
+#   pragma warning( disable : 4786 )  // specifier longer then 255 chars
 #endif
 
+#ifdef _PreComp_
+
 // standard
 #include <iostream>
 #include <sstream>
diff --git a/src/Mod/Spreadsheet/App/PropertyColumnWidths.h b/src/Mod/Spreadsheet/App/PropertyColumnWidths.h
index 8f3bbcbd2..9adfe17c0 100644
--- a/src/Mod/Spreadsheet/App/PropertyColumnWidths.h
+++ b/src/Mod/Spreadsheet/App/PropertyColumnWidths.h
@@ -45,7 +45,10 @@ public:
         return *this;
     }
 
-    int getValue(int column) const { return find(column) != end() ? at(column) : defaultWidth; }
+    int getValue(int column) const {
+        std::map<int, int>::const_iterator i = find(column);
+        return i != end() ? i->second : defaultWidth;
+    }
 
     virtual Property *Copy(void) const;
 
diff --git a/src/Mod/Spreadsheet/App/PropertyRowHeights.h b/src/Mod/Spreadsheet/App/PropertyRowHeights.h
index 3ec58ff4a..3042c16b2 100644
--- a/src/Mod/Spreadsheet/App/PropertyRowHeights.h
+++ b/src/Mod/Spreadsheet/App/PropertyRowHeights.h
@@ -41,7 +41,10 @@ public:
 
     void setValue(int row, int height);
 
-    int getValue(int row) const { return find(row) != end() ? at(row) : 20; }
+    int getValue(int row) const {
+        std::map<int, int>::const_iterator i = find(row);
+        return i != end() ? i->second : defaultHeight;
+    }
 
     std::map<int, int> getValues() const {
         return *this;
diff --git a/src/Mod/Spreadsheet/App/PropertySheet.cpp b/src/Mod/Spreadsheet/App/PropertySheet.cpp
index 9c3e8645c..75e34d759 100644
--- a/src/Mod/Spreadsheet/App/PropertySheet.cpp
+++ b/src/Mod/Spreadsheet/App/PropertySheet.cpp
@@ -147,8 +147,9 @@ void PropertySheet::setDirty(CellAddress address)
 {
     /* Merged cells will automatically force an update of the top left cell
        to be consistent. */
-    if (mergedCells.find(address) != mergedCells.end())
-        address = mergedCells[address];
+    std::map<CellAddress, CellAddress>::const_iterator i = mergedCells.find(address);
+    if (i != mergedCells.end())
+        address = i->second;
 
     dirty.insert(address);
 }
@@ -287,7 +288,7 @@ void PropertySheet::Restore(Base::XMLReader &reader)
                 mergeCells(address, CellAddress(address.row() + rows - 1, address.col() + cols - 1));
             }
         }
-        catch (const Base::Exception & e) {
+        catch (const Base::Exception &) {
             // Something is wrong, skip this cell
         }
         catch (...) {
@@ -298,66 +299,61 @@ void PropertySheet::Restore(Base::XMLReader &reader)
 
 Cell * PropertySheet::cellAt(CellAddress address)
 {
-    std::map<CellAddress, Cell*>::iterator i = data.find(address);
+    std::map<CellAddress, CellAddress>::const_iterator j = mergedCells.find(address);
 
-    if (i == data.end()) {
-        if (mergedCells.find(address) != mergedCells.end()) {
-            std::map<CellAddress, CellAddress>::iterator j = mergedCells.find(address);
+    // address actually inside a merged cell
+    if (j != mergedCells.end()) {
+        std::map<CellAddress, Cell*>::const_iterator i = data.find(j->second);
+        assert(i != data.end());
 
-            assert(j != mergedCells.end());
-
-            i = data.find(j->second);
-            assert(i != data.end());
-
-            return i->second;
-        }
-        return 0;
+        return i->second;
     }
+
+    std::map<CellAddress, Cell*>::const_iterator i = data.find(address);
+
+    if (i == data.end())
+        return 0;
     else
         return i->second;
 }
 
 const Cell * PropertySheet::cellAt(CellAddress address) const
 {
+    std::map<CellAddress, CellAddress>::const_iterator j = mergedCells.find(address);
+
+    // address actually inside a merged cell
+    if (j != mergedCells.end()) {
+        std::map<CellAddress, Cell*>::const_iterator i = data.find(j->second);
+        assert(i != data.end());
+
+        return i->second;
+    }
+
     std::map<CellAddress, Cell*>::const_iterator i = data.find(address);
 
-    if (i == data.end()) {
-        if (mergedCells.find(address) != mergedCells.end()) {
-            std::map<CellAddress, CellAddress>::const_iterator j = mergedCells.find(address);
-
-            assert(j != mergedCells.end());
-
-            i = data.find(j->second);
-            assert(i != data.end());
-
-            return i->second;
-        }
-
+    if (i == data.end())
         return 0;
-    }
     else
         return i->second;
 }
 
 Cell * PropertySheet::nonNullCellAt(CellAddress address)
 {
+    std::map<CellAddress, CellAddress>::const_iterator j = mergedCells.find(address);
+
+    if (j != mergedCells.end()) {
+        std::map<CellAddress, Cell*>::const_iterator i = data.find(j->second);
+
+        if (i == data.end())
+            return createCell(address);
+        else
+            return i->second;
+    }
+
     std::map<CellAddress, Cell*>::const_iterator i = data.find(address);
 
-    if (i == data.end()) {
-        if (mergedCells.find(address) != mergedCells.end()) {
-            std::map<CellAddress, CellAddress>::const_iterator j = mergedCells.find(address);
-
-            assert(j != mergedCells.end());
-
-            i = data.find(j->second);
-            if (i == data.end())
-                return createCell(address);
-            else
-                return i->second;
-        }
-
+    if (i == data.end())
         return createCell(address);
-    }
     else
         return i->second;
 }
@@ -453,8 +449,7 @@ void PropertySheet::moveCell(CellAddress currPos, CellAddress newPos)
         clear(newPos);
 
     if (i != data.end()) {
-        int row, col;
-        Cell * cell = data.at(currPos);
+        Cell * cell = i->second;
 
         // Remove from old
         removeDependencies(currPos);
@@ -540,7 +535,11 @@ void PropertySheet::insertRows(int row, int count)
 
     Signaller signaller(*this);
     for (std::vector<CellAddress>::const_reverse_iterator i = keys.rbegin(); i != keys.rend(); ++i) {
-        Cell * cell = data.at(*i);
+        std::map<CellAddress, Cell*>::iterator j = data.find(*i);
+
+        assert(j != data.end());
+
+        Cell * cell = j->second;
 
         // Visit each cell to make changes to expressions if necessary
         visitor.reset();
@@ -581,7 +580,11 @@ void PropertySheet::removeRows(int row, int count)
 
     Signaller signaller(*this);
     for (std::vector<CellAddress>::const_iterator i = keys.begin(); i != keys.end(); ++i) {
-        Cell * cell = data.at(*i);
+        std::map<CellAddress, Cell*>::iterator j = data.find(*i);
+
+        assert(j != data.end());
+
+        Cell * cell = j->second;
 
         // Visit each cell to make changes to expressions if necessary
         visitor.reset();
@@ -613,7 +616,11 @@ void PropertySheet::insertColumns(int col, int count)
 
     Signaller signaller(*this);
     for (std::vector<CellAddress>::const_reverse_iterator i = keys.rbegin(); i != keys.rend(); ++i) {
-        Cell * cell = data.at(*i);
+        std::map<CellAddress, Cell*>::iterator j = data.find(*i);
+
+        assert(j != data.end());
+
+        Cell * cell = j->second;
 
         // Visit each cell to make changes to expressions if necessary
         visitor.reset();
@@ -654,7 +661,11 @@ void PropertySheet::removeColumns(int col, int count)
 
     Signaller signaller(*this);
     for (std::vector<CellAddress>::const_iterator i = keys.begin(); i != keys.end(); ++i) {
-        Cell * cell = data.at(*i);
+        std::map<CellAddress, Cell*>::iterator j = data.find(*i);
+
+        assert(j != data.end());
+
+        Cell * cell = j->second;
 
         // Visit each cell to make changes to expressions if necessary
         visitor.reset();
@@ -692,7 +703,7 @@ bool PropertySheet::mergeCells(CellAddress from, CellAddress to)
     // Clear cells that will be hidden by the merge
     for (int r = from.row(); r <= to.row(); ++r)
         for (int c = from.col(); c <= to.col(); ++c)
-            if ( !(r == from.row() && c == to.row()) )
+            if ( !(r == from.row() && c == from.col()) )
                 clear(CellAddress(r, c));
 
     // Update internal structure to track merged cells
@@ -710,14 +721,14 @@ bool PropertySheet::mergeCells(CellAddress from, CellAddress to)
 void PropertySheet::splitCell(CellAddress address)
 {
     int rows, cols;
+    std::map<CellAddress, CellAddress>::const_iterator i = mergedCells.find(address);
 
-    if (mergedCells.find(address) == mergedCells.end())
+    if (i == mergedCells.end())
         return;
 
-    cellAt(address)->getSpans(rows, cols);
-
-    CellAddress anchor = mergedCells.at(address);
+    CellAddress anchor = i->second;
     Signaller signaller(*this);
+    cellAt(anchor)->getSpans(rows, cols);
 
     for (int r = anchor.row(); r <= anchor.row() + rows; ++r)
         for (int c = anchor.col(); c <= anchor.col() + cols; ++c) {
@@ -730,8 +741,10 @@ void PropertySheet::splitCell(CellAddress address)
 
 void PropertySheet::getSpans(CellAddress address, int & rows, int & cols) const
 {
-    if (mergedCells.find(address) != mergedCells.end()) {
-        CellAddress anchor = mergedCells.at(address);
+    std::map<CellAddress, CellAddress>::const_iterator i = mergedCells.find(address);
+
+    if (i != mergedCells.end()) {
+        CellAddress anchor = i->second;
 
         cellAt(anchor)->getSpans(rows, cols);
     }
@@ -747,7 +760,9 @@ bool PropertySheet::isMergedCell(CellAddress address) const
 
 bool PropertySheet::isHidden(CellAddress address) const
 {
-    return mergedCells.find(address) != mergedCells.end() && mergedCells.at(address) != address;
+    std::map<CellAddress, CellAddress>::const_iterator i = mergedCells.find(address);
+
+    return i != mergedCells.end() && i->second != address;
 }
 
 /**
@@ -839,7 +854,11 @@ void PropertySheet::removeDependencies(CellAddress key)
     j = i1->second.begin();
 
     while (j != i1->second.end()) {
-        propertyNameToCellMap.at(*j).erase(key);
+        std::map<std::string, std::set< CellAddress > >::iterator k = propertyNameToCellMap.find(*j);
+
+        assert(k != propertyNameToCellMap.end());
+
+        k->second.erase(key);
         ++j;
     }
 
@@ -855,7 +874,11 @@ void PropertySheet::removeDependencies(CellAddress key)
     j = i2->second.begin();
 
     while (j != i2->second.end()) {
-        documentObjectToCellMap.at(*j).erase(key);
+        std::map<std::string, std::set< CellAddress > >::iterator k = documentObjectToCellMap.find(*j);
+
+        assert(k != documentObjectToCellMap.end());
+
+        k->second.erase(key);
         ++j;
     }
 
@@ -997,9 +1020,10 @@ void PropertySheet::recomputeDependants(const DocumentObject *docObj)
 const std::set<CellAddress> &PropertySheet::getDeps(const std::string &name) const
 {
     static std::set<CellAddress> empty;
+    std::map<std::string, std::set< CellAddress > >::const_iterator i = propertyNameToCellMap.find(name);
 
-    if (propertyNameToCellMap.find(name) != propertyNameToCellMap.end())
-        return propertyNameToCellMap.at(name);
+    if (i != propertyNameToCellMap.end())
+        return i->second;
     else
         return empty;
 }
@@ -1007,9 +1031,10 @@ const std::set<CellAddress> &PropertySheet::getDeps(const std::string &name) con
 const std::set<std::string> &PropertySheet::getDeps(CellAddress pos) const
 {
     static std::set<std::string> empty;
+    std::map<CellAddress, std::set< std::string > >::const_iterator i = cellToPropertyNameMap.find(pos);
 
-    if (cellToPropertyNameMap.find(pos) != cellToPropertyNameMap.end())
-        return cellToPropertyNameMap.at(pos);
+    if (i != cellToPropertyNameMap.end())
+        return i->second;
     else
         return empty;
 }
diff --git a/src/Mod/Spreadsheet/App/Sheet.cpp b/src/Mod/Spreadsheet/App/Sheet.cpp
index 586ddd7f0..637357820 100644
--- a/src/Mod/Spreadsheet/App/Sheet.cpp
+++ b/src/Mod/Spreadsheet/App/Sheet.cpp
@@ -212,7 +212,7 @@ static void writeEscaped(std::string const& s, char quoteChar, char escapeChar,
 bool Sheet::exportToFile(const std::string &filename, char delimiter, char quoteChar, char escapeChar) const
 {
     std::ofstream file;
-    int row, col, prevRow = -1, prevCol = -1;
+    int prevRow = -1, prevCol = -1;
 
     file.open(filename.c_str(), std::ios::out | std::ios::ate | std::ios::binary);
 
@@ -493,7 +493,6 @@ Property * Sheet::setFloatProperty(CellAddress key, double value)
 
 Property * Sheet::setQuantityProperty(CellAddress key, double value, const Base::Unit & unit)
 {
-    int row, col;
     Property * prop = props.getPropertyByName(toAddress(key).c_str());
     PropertyQuantity * quantityProp;
 
diff --git a/src/Mod/Spreadsheet/App/Sheet.h b/src/Mod/Spreadsheet/App/Sheet.h
index d39d06d86..aacecf015 100644
--- a/src/Mod/Spreadsheet/App/Sheet.h
+++ b/src/Mod/Spreadsheet/App/Sheet.h
@@ -193,7 +193,7 @@ public:
     }
 
     short getPropertyType(const App::Property *prop) const {
-        props.getPropertyType(prop);
+        return props.getPropertyType(prop);
     }
 
     /// get the name of a property
diff --git a/src/Mod/Spreadsheet/App/SheetPyImp.cpp b/src/Mod/Spreadsheet/App/SheetPyImp.cpp
index 7b81d573a..54c311084 100644
--- a/src/Mod/Spreadsheet/App/SheetPyImp.cpp
+++ b/src/Mod/Spreadsheet/App/SheetPyImp.cpp
@@ -416,7 +416,6 @@ PyObject* SheetPy::getStyle(PyObject *args)
 
 PyObject* SheetPy::setDisplayUnit(PyObject *args)
 {
-    int row, col;
     const char * cell;
     const char * value;
 
@@ -842,7 +841,6 @@ PyObject* SheetPy::setRowHeight(PyObject *args)
 PyObject* SheetPy::getRowHeight(PyObject *args)
 {
     const char * rowStr;
-    int row, col;
 
     if (!PyArg_ParseTuple(args, "s:getRowHeight", &rowStr))
         return 0;
diff --git a/src/Mod/Spreadsheet/Gui/SheetModel.cpp b/src/Mod/Spreadsheet/Gui/SheetModel.cpp
index edd9b91c5..f3a85abd1 100644
--- a/src/Mod/Spreadsheet/Gui/SheetModel.cpp
+++ b/src/Mod/Spreadsheet/Gui/SheetModel.cpp
@@ -355,6 +355,8 @@ QVariant SheetModel::data(const QModelIndex &index, int role) const
             return QVariant();
         }
     }
+
+    return QVariant();
 }
 
 QVariant SheetModel::headerData(int section, Qt::Orientation orientation, int role) const