diff --git a/FlatCAMApp.py b/FlatCAMApp.py
index fcc0f629..32b33f85 100644
--- a/FlatCAMApp.py
+++ b/FlatCAMApp.py
@@ -3959,7 +3959,7 @@ class App(QtCore.QObject):
     def on_toggle_units_click(self):
         try:
             self.ui.general_defaults_form.general_app_group.units_radio.activated_custom.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         if self.defaults["units"] == 'MM':
@@ -5180,7 +5180,7 @@ class App(QtCore.QObject):
         # this disconnect() is done so the slot will be connected only once
         try:
             self.ui.plot_tab_area.tab_closed_signal.disconnect(self.on_preferences_closed)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         self.ui.plot_tab_area.tab_closed_signal.connect(self.on_preferences_closed)
 
@@ -5190,7 +5190,7 @@ class App(QtCore.QObject):
                 try:
                     try:
                         tb.textEdited.disconnect(self.on_preferences_edited)
-                    except TypeError:
+                    except (TypeError, AttributeError):
                         pass
                     tb.textEdited.connect(self.on_preferences_edited)
                 except AttributeError:
@@ -5199,7 +5199,7 @@ class App(QtCore.QObject):
                 try:
                     try:
                         tb.modificationChanged.disconnect(self.on_preferences_edited)
-                    except TypeError:
+                    except (TypeError, AttributeError):
                         pass
                     tb.modificationChanged.connect(self.on_preferences_edited)
                 except AttributeError:
@@ -5208,7 +5208,7 @@ class App(QtCore.QObject):
                 try:
                     try:
                         tb.toggled.disconnect(self.on_preferences_edited)
-                    except TypeError:
+                    except (TypeError, AttributeError):
                         pass
                     tb.toggled.connect(self.on_preferences_edited)
                 except AttributeError:
@@ -5217,7 +5217,7 @@ class App(QtCore.QObject):
                 try:
                     try:
                         tb.valueChanged.disconnect(self.on_preferences_edited)
-                    except TypeError:
+                    except (TypeError, AttributeError):
                         pass
                     tb.valueChanged.connect(self.on_preferences_edited)
                 except AttributeError:
@@ -5226,7 +5226,7 @@ class App(QtCore.QObject):
                 try:
                     try:
                         tb.currentIndexChanged.disconnect(self.on_preferences_edited)
-                    except TypeError:
+                    except (TypeError, AttributeError):
                         pass
                     tb.currentIndexChanged.connect(self.on_preferences_edited)
                 except AttributeError:
diff --git a/FlatCAMObj.py b/FlatCAMObj.py
index d3f83bd0..b5944183 100644
--- a/FlatCAMObj.py
+++ b/FlatCAMObj.py
@@ -582,7 +582,7 @@ class FlatCAMGerber(FlatCAMObj, Gerber):
         try:
             # if connected, disconnect the signal from the slot on item_changed as it creates issues
             self.ui.apertures_table.itemChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         self.apertures_row = 0
@@ -726,12 +726,12 @@ class FlatCAMGerber(FlatCAMObj, Gerber):
         for row in range(self.ui.apertures_table.rowCount()):
             try:
                 self.ui.apertures_table.cellWidget(row, 5).clicked.disconnect()
-            except TypeError:
+            except (TypeError, AttributeError):
                 pass
 
         try:
             self.ui.mark_all_cb.clicked.disconnect(self.on_mark_all_click)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def on_generatenoncopper_button_click(self, *args):
@@ -1832,7 +1832,7 @@ class FlatCAMExcellon(FlatCAMObj, Excellon):
         try:
             # if connected, disconnect the signal from the slot on item_changed as it creates issues
             self.ui.tools_table.itemChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         n = len(self.tools)
@@ -2120,12 +2120,12 @@ class FlatCAMExcellon(FlatCAMObj, Excellon):
         for row in range(self.ui.tools_table.rowCount()):
             try:
                 self.ui.tools_table.cellWidget(row, 5).clicked.disconnect()
-            except TypeError:
+            except (TypeError, AttributeError):
                 pass
 
         try:
             self.ui.plot_cb.stateChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def on_tool_offset_edit(self):
@@ -3501,66 +3501,66 @@ class FlatCAMGeometry(FlatCAMObj, Geometry):
             if isinstance(current_widget, FCCheckBox):
                 try:
                     self.ui.grid3.itemAt(i).widget().stateChanged.disconnect(self.gui_form_to_storage)
-                except TypeError:
+                except (TypeError, AttributeError):
                     pass
             elif isinstance(current_widget, FCComboBox):
                 try:
                     self.ui.grid3.itemAt(i).widget().currentIndexChanged.disconnect(self.gui_form_to_storage)
-                except TypeError:
+                except (TypeError, AttributeError):
                     pass
             elif isinstance(current_widget, LengthEntry) or isinstance(current_widget, IntEntry) or \
                     isinstance(current_widget, FCEntry) or isinstance(current_widget, FloatEntry):
                 try:
                     self.ui.grid3.itemAt(i).widget().editingFinished.disconnect(self.gui_form_to_storage)
-                except TypeError:
+                except (TypeError, AttributeError):
                     pass
 
         for row in range(self.ui.geo_tools_table.rowCount()):
             for col in [2, 3, 4]:
                 try:
                     self.ui.geo_tools_table.cellWidget(row, col).currentIndexChanged.disconnect()
-                except TypeError:
+                except (TypeError, AttributeError):
                     pass
 
         try:
             self.ui.addtool_btn.clicked.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.ui.copytool_btn.clicked.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.ui.deltool_btn.clicked.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.ui.geo_tools_table.currentItemChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.ui.geo_tools_table.itemChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.ui.tool_offset_entry.editingFinished.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         for row in range(self.ui.geo_tools_table.rowCount()):
             try:
                 self.ui.geo_tools_table.cellWidget(row, 6).clicked.disconnect()
-            except TypeError:
+            except (TypeError, AttributeError):
                 pass
 
         try:
             self.ui.plot_cb.stateChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def on_tool_add(self, dia=None):
@@ -5546,7 +5546,7 @@ class FlatCAMCNCjob(FlatCAMObj, CNCjob):
 
         try:
             self.ui.annotation_cb.stateChanged.disconnect(self.on_annotation_change)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         self.ui.annotation_cb.stateChanged.connect(self.on_annotation_change)
 
@@ -5590,7 +5590,7 @@ class FlatCAMCNCjob(FlatCAMObj, CNCjob):
             self.ui.cnc_tools_table.cellWidget(row, 6).clicked.disconnect(self.on_plot_cb_click_table)
         try:
             self.ui.plot_cb.stateChanged.disconnect(self.on_plot_cb_click)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def on_updateplot_button_click(self, *args):
diff --git a/README.md b/README.md
index d31a0a09..2995b969 100644
--- a/README.md
+++ b/README.md
@@ -19,6 +19,7 @@ CAD program, and create G-Code for Isolation routing.
 - created a new menu entry in the File menu named Recent projects that will hold the recent projects and the previous "Recent files" will hold only the previous loaded files
 - updated all translations for the new strings
 - fixed bug recently introduced that when changing the units in the Edit -> Preferences it did not converted the values
+- fixed another bug that when selecting an Excellon object after disabling it it crashed the app
 - RELEASE 8.92
 
 30.07.2019
diff --git a/flatcamEditors/FlatCAMExcEditor.py b/flatcamEditors/FlatCAMExcEditor.py
index ea071f3c..7c5e8726 100644
--- a/flatcamEditors/FlatCAMExcEditor.py
+++ b/flatcamEditors/FlatCAMExcEditor.py
@@ -669,7 +669,7 @@ class FCDrillSelect(DrawTool):
             # select the diameter of the selected shape in the tool table
             try:
                 self.draw_app.tools_table_exc.cellPressed.disconnect()
-            except TypeError:
+            except (TypeError, AttributeError):
                 pass
 
             sel_tools = set()
@@ -1258,12 +1258,12 @@ class FlatCAMExcEditor(QtCore.QObject):
         try:
             # if connected, disconnect the signal from the slot on item_changed as it creates issues
             self.tools_table_exc.itemChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.tools_table_exc.cellPressed.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         # updated units
@@ -1820,17 +1820,17 @@ class FlatCAMExcEditor(QtCore.QObject):
 
         try:
             self.app.ui.popmenu_copy.triggered.disconnect(self.exc_copy_drills)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.popmenu_delete.triggered.disconnect(self.on_delete_btn)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.popmenu_move.triggered.disconnect(self.exc_move_drills)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         self.app.ui.popmenu_copy.triggered.connect(self.app.on_copy_object)
@@ -1840,12 +1840,12 @@ class FlatCAMExcEditor(QtCore.QObject):
         # Excellon Editor
         try:
             self.app.ui.drill.triggered.disconnect(self.exc_add_drill)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.drill_array.triggered.disconnect(self.exc_add_drill_array)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def clear(self):
diff --git a/flatcamEditors/FlatCAMGeoEditor.py b/flatcamEditors/FlatCAMGeoEditor.py
index 07e92f37..86e08665 100644
--- a/flatcamEditors/FlatCAMGeoEditor.py
+++ b/flatcamEditors/FlatCAMGeoEditor.py
@@ -3296,15 +3296,15 @@ class FlatCAMGeoEditor(QtCore.QObject):
 
         try:
             self.app.ui.popmenu_copy.triggered.disconnect(lambda: self.select_tool('copy'))
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         try:
             self.app.ui.popmenu_delete.triggered.disconnect(self.on_delete_btn)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         try:
             self.app.ui.popmenu_move.triggered.disconnect(lambda: self.select_tool('move'))
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         self.app.ui.popmenu_copy.triggered.connect(self.app.on_copy_object)
@@ -3314,22 +3314,22 @@ class FlatCAMGeoEditor(QtCore.QObject):
         # Geometry Editor
         try:
             self.app.ui.draw_line.triggered.disconnect(self.draw_tool_path)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.draw_rect.triggered.disconnect(self.draw_tool_rectangle)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.draw_cut.triggered.disconnect(self.cutpath)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.draw_move.triggered.disconnect(self.on_move)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def add_shape(self, shape):
diff --git a/flatcamEditors/FlatCAMGrbEditor.py b/flatcamEditors/FlatCAMGrbEditor.py
index 11a6de72..041a5bcb 100644
--- a/flatcamEditors/FlatCAMGrbEditor.py
+++ b/flatcamEditors/FlatCAMGrbEditor.py
@@ -1693,7 +1693,7 @@ class FCScale(FCShapeTool):
 
         try:
             self.draw_app.scale_button.clicked.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         self.draw_app.scale_button.clicked.connect(self.on_scale_click)
 
@@ -1735,7 +1735,7 @@ class FCBuffer(FCShapeTool):
 
         try:
             self.draw_app.buffer_button.clicked.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         self.draw_app.buffer_button.clicked.connect(self.on_buffer_click)
 
@@ -1777,7 +1777,7 @@ class FCMarkArea(FCShapeTool):
 
         try:
             self.draw_app.ma_threshold__button.clicked.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         self.draw_app.ma_threshold__button.clicked.connect(self.on_markarea_click)
 
@@ -2934,12 +2934,12 @@ class FlatCAMGrbEditor(QtCore.QObject):
         try:
             # if connected, disconnect the signal from the slot on item_changed as it creates issues
             self.apertures_table.itemChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.apertures_table.cellPressed.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         # updated units
@@ -3488,17 +3488,17 @@ class FlatCAMGrbEditor(QtCore.QObject):
 
         try:
             self.app.ui.popmenu_copy.triggered.disconnect(self.on_copy_button)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.popmenu_delete.triggered.disconnect(self.on_delete_btn)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.popmenu_move.triggered.disconnect(self.on_move_button)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         self.app.ui.popmenu_copy.triggered.connect(self.app.on_copy_object)
@@ -3509,22 +3509,22 @@ class FlatCAMGrbEditor(QtCore.QObject):
 
         try:
             self.app.ui.grb_draw_pad.triggered.disconnect(self.on_pad_add)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.grb_draw_pad_array.triggered.disconnect(self.on_pad_add_array)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.grb_draw_track.triggered.disconnect(self.on_track_add)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.app.ui.grb_draw_region.triggered.disconnect(self.on_region_add)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def clear(self):
diff --git a/flatcamTools/ToolNonCopperClear.py b/flatcamTools/ToolNonCopperClear.py
index b858c8ed..9e36da34 100644
--- a/flatcamTools/ToolNonCopperClear.py
+++ b/flatcamTools/ToolNonCopperClear.py
@@ -461,7 +461,7 @@ class NonCopperClear(FlatCAMTool, Gerber):
         try:
             # if connected, disconnect the signal from the slot on item_changed as it creates issues
             self.tools_table.itemChanged.disconnect(self.on_tool_edit)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def on_tool_add(self, dia=None, muted=None):
diff --git a/flatcamTools/ToolPDF.py b/flatcamTools/ToolPDF.py
index 718a856d..5e8267b0 100644
--- a/flatcamTools/ToolPDF.py
+++ b/flatcamTools/ToolPDF.py
@@ -366,7 +366,7 @@ class ToolPDF(FlatCAMTool):
         self.check_thread.setInterval(check_period)
         try:
             self.check_thread.timeout.disconnect(self.periodic_check_handler)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         self.check_thread.timeout.connect(self.periodic_check_handler)
diff --git a/flatcamTools/ToolPaint.py b/flatcamTools/ToolPaint.py
index 9c689a16..24678f81 100644
--- a/flatcamTools/ToolPaint.py
+++ b/flatcamTools/ToolPaint.py
@@ -437,7 +437,7 @@ class ToolPaint(FlatCAMTool, Gerber):
         try:
             # if connected, disconnect the signal from the slot on item_changed as it creates issues
             self.tools_table.itemChanged.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         # updated units
diff --git a/flatcamTools/ToolSolderPaste.py b/flatcamTools/ToolSolderPaste.py
index 5ca85d1a..0bac7e1d 100644
--- a/flatcamTools/ToolSolderPaste.py
+++ b/flatcamTools/ToolSolderPaste.py
@@ -646,22 +646,22 @@ class SolderPaste(FlatCAMTool):
             if isinstance(self.gcode_form_layout.itemAt(i).widget(), FCComboBox):
                 try:
                     self.gcode_form_layout.itemAt(i).widget().currentIndexChanged.disconnect()
-                except TypeError:
+                except (TypeError, AttributeError):
                     pass
             if isinstance(self.gcode_form_layout.itemAt(i).widget(), FCEntry):
                 try:
                     self.gcode_form_layout.itemAt(i).widget().editingFinished.disconnect()
-                except TypeError:
+                except (TypeError, AttributeError):
                     pass
 
         try:
             self.tools_table.itemChanged.disconnect(self.on_tool_edit)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         try:
             self.tools_table.currentItemChanged.disconnect(self.on_row_selection_change)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
     def update_comboboxes(self, obj, status):
diff --git a/flatcamTools/ToolSub.py b/flatcamTools/ToolSub.py
index d4f200d3..7f6cab59 100644
--- a/flatcamTools/ToolSub.py
+++ b/flatcamTools/ToolSub.py
@@ -175,13 +175,13 @@ class ToolSub(FlatCAMTool):
 
         try:
             self.intersect_btn.clicked.disconnect(self.on_grb_intersection_click)
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         self.intersect_btn.clicked.connect(self.on_grb_intersection_click)
 
         try:
             self.intersect_geo_btn.clicked.disconnect()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
         self.intersect_geo_btn.clicked.connect(self.on_geo_intersection_click)
 
@@ -569,14 +569,14 @@ class ToolSub(FlatCAMTool):
 
         try:
             self.check_thread.stop()
-        except TypeError:
+        except (TypeError, AttributeError):
             pass
 
         if reset:
             self.check_thread.setInterval(check_period)
             try:
                 self.check_thread.timeout.disconnect(self.periodic_check_handler)
-            except TypeError:
+            except (TypeError, AttributeError):
                 pass
 
         self.check_thread.timeout.connect(self.periodic_check_handler)