diff --git a/cura/ConvexHullNode.py b/cura/ConvexHullNode.py
index b99e80fcff6..1c3d8f88dbc 100644
--- a/cura/ConvexHullNode.py
+++ b/cura/ConvexHullNode.py
@@ -33,7 +33,7 @@ def __init__(self, node, hull, parent = None):
         self._convex_hull_head_mesh = None
         self._hull = hull
 
-        hull_points = self._hull.getPoints()
+        hull_points = self._hull.getPoints() # TODO: @UnusedVariable
         hull_mesh = self.createHullMesh(self._hull.getPoints())
         if hull_mesh:
             self.setMeshData(hull_mesh)
diff --git a/cura/CuraActions.py b/cura/CuraActions.py
index 36bf32fdd77..dd11eb2b979 100644
--- a/cura/CuraActions.py
+++ b/cura/CuraActions.py
@@ -1,4 +1,4 @@
-from PyQt5.QtCore import QObject, pyqtSlot, pyqtProperty, QUrl
+from PyQt5.QtCore import QObject, pyqtSlot, QUrl
 from PyQt5.QtGui import QDesktopServices
 
 from UM.Event import CallFunctionEvent
diff --git a/cura/CuraApplication.py b/cura/CuraApplication.py
index 0f35a3dd982..e5813fb7906 100644
--- a/cura/CuraApplication.py
+++ b/cura/CuraApplication.py
@@ -6,22 +6,16 @@
 from UM.Scene.Camera import Camera
 from UM.Scene.Platform import Platform
 from UM.Math.Vector import Vector
-from UM.Math.Matrix import Matrix
 from UM.Math.Quaternion import Quaternion
 from UM.Math.AxisAlignedBox import AxisAlignedBox
 from UM.Resources import Resources
 from UM.Scene.ToolHandle import ToolHandle
 from UM.Scene.Iterator.DepthFirstIterator import DepthFirstIterator
-from UM.Mesh.WriteMeshJob import WriteMeshJob
 from UM.Mesh.ReadMeshJob import ReadMeshJob
 from UM.Logger import Logger
 from UM.Preferences import Preferences
-from UM.Message import Message
-from UM.PluginRegistry import PluginRegistry
 from UM.JobQueue import JobQueue
-from UM.Math.Polygon import Polygon
 
-from UM.Scene.BoxRenderer import BoxRenderer
 from UM.Scene.Selection import Selection
 from UM.Scene.GroupDecorator import GroupDecorator
 
@@ -41,7 +35,7 @@
 from . import ZOffsetDecorator
 from . import CuraSplashScreen
 
-from PyQt5.QtCore import pyqtSlot, QUrl, Qt, pyqtSignal, pyqtProperty, QEvent, Q_ENUMS
+from PyQt5.QtCore import pyqtSlot, QUrl, pyqtSignal, pyqtProperty, QEvent, Q_ENUMS
 from PyQt5.QtGui import QColor, QIcon
 from PyQt5.QtQml import qmlRegisterUncreatableType
 
@@ -353,7 +347,7 @@ def multiplyObject(self, object_id, count):
 
         if node:
             op = GroupedOperation()
-            for i in range(count):
+            for _ in range(count):
                 if node.getParent() and node.getParent().callDecoration("isGroup"):
                     new_node = copy.deepcopy(node.getParent()) #Copy the group node.
                     new_node.callDecoration("setConvexHull",None)
@@ -528,6 +522,7 @@ def mergeSelected(self):
         try:
             group_node = Selection.getAllSelectedObjects()[0]
         except Exception as e:
+            Logger.log("d", "mergeSelected: Exception:", e)
             return
         multi_material_decorator = MultiMaterialDecorator.MultiMaterialDecorator()
         group_node.addDecorator(multi_material_decorator)
diff --git a/cura/LayerData.py b/cura/LayerData.py
index 90529e63eaa..dc9b4faa0ec 100644
--- a/cura/LayerData.py
+++ b/cura/LayerData.py
@@ -7,8 +7,6 @@
 from UM.Math.Vector import Vector
 
 import numpy
-import math
-import copy
 
 class LayerData(MeshData):
     def __init__(self):
@@ -20,11 +18,11 @@ def addLayer(self, layer):
         if layer not in self._layers:
             self._layers[layer] = Layer(layer)
 
-    def addPolygon(self, layer, type, data, line_width):
+    def addPolygon(self, layer, polygon_type, data, line_width):
         if layer not in self._layers:
             self.addLayer(layer)
 
-        p = Polygon(self, type, data, line_width)
+        p = Polygon(self, polygon_type, data, line_width)
         self._layers[layer].polygons.append(p)
 
     def getLayer(self, layer):
@@ -69,8 +67,8 @@ def build(self):
         self.addIndices(indices.flatten())
 
 class Layer():
-    def __init__(self, id):
-        self._id = id
+    def __init__(self, layer_id):
+        self._id = layer_id
         self._height = 0.0
         self._thickness = 0.0
         self._polygons = []
@@ -173,9 +171,9 @@ class Polygon():
     MoveCombingType = 8
     MoveRetractionType = 9
 
-    def __init__(self, mesh, type, data, line_width):
+    def __init__(self, mesh, polygon_type, data, line_width):
         self._mesh = mesh
-        self._type = type
+        self._type = polygon_type
         self._data = data
         self._line_width = line_width / 1000
 
diff --git a/cura/PlatformPhysics.py b/cura/PlatformPhysics.py
index f660d68f34d..b8934b87969 100644
--- a/cura/PlatformPhysics.py
+++ b/cura/PlatformPhysics.py
@@ -5,8 +5,6 @@
 
 from UM.Scene.SceneNode import SceneNode
 from UM.Scene.Iterator.BreadthFirstIterator import BreadthFirstIterator
-from UM.Operations.TranslateOperation import TranslateOperation
-from UM.Math.Float import Float
 from UM.Math.Vector import Vector
 from UM.Math.AxisAlignedBox import AxisAlignedBox
 from UM.Application import Application
diff --git a/cura/PlatformPhysicsOperation.py b/cura/PlatformPhysicsOperation.py
index c307ae5ae91..5d2089e8af5 100644
--- a/cura/PlatformPhysicsOperation.py
+++ b/cura/PlatformPhysicsOperation.py
@@ -2,8 +2,6 @@
 # Cura is released under the terms of the AGPLv3 or higher.
 
 from UM.Operations.Operation import Operation
-from UM.Operations.AddSceneNodeOperation import AddSceneNodeOperation
-from UM.Operations.TranslateOperation import TranslateOperation
 from UM.Operations.GroupedOperation import GroupedOperation
 
 ##  A specialised operation designed specifically to modify the previous operation.
diff --git a/cura/PrintInformation.py b/cura/PrintInformation.py
index 73dde534379..d3eaab662c5 100644
--- a/cura/PrintInformation.py
+++ b/cura/PrintInformation.py
@@ -1,11 +1,9 @@
 # Copyright (c) 2015 Ultimaker B.V.
 # Cura is released under the terms of the AGPLv3 or higher.
 
-from PyQt5.QtCore import QObject, QDateTime, QTimer, pyqtSignal, pyqtSlot, pyqtProperty
+from PyQt5.QtCore import QObject, pyqtSignal, pyqtProperty
 
 from UM.Application import Application
-from UM.Resources import Resources
-from UM.Scene.SceneNode import SceneNode
 from UM.Qt.Duration import Duration
 
 import math
diff --git a/plugins/ChangeLogPlugin/ChangeLog.py b/plugins/ChangeLogPlugin/ChangeLog.py
index 7586268aa64..b1f65a00350 100644
--- a/plugins/ChangeLogPlugin/ChangeLog.py
+++ b/plugins/ChangeLogPlugin/ChangeLog.py
@@ -42,7 +42,7 @@ def getChangeLogs(self):
     @pyqtSlot(result = str)
     def getChangeLogString(self):
         logs = self.getChangeLogs()
-        latest_version = Version(Preferences.getInstance().getValue("general/latest_version_changelog_shown"))
+        latest_version = Version(Preferences.getInstance().getValue("general/latest_version_changelog_shown")) #TODO: @UnusedVariable
         result = ""
         for version in logs:
             result += "<h1>" + str(version) + "</h1><br>"
diff --git a/plugins/CuraEngineBackend/CuraEngineBackend.py b/plugins/CuraEngineBackend/CuraEngineBackend.py
index 7f7b9924046..70feba9974f 100644
--- a/plugins/CuraEngineBackend/CuraEngineBackend.py
+++ b/plugins/CuraEngineBackend/CuraEngineBackend.py
@@ -4,25 +4,19 @@
 from UM.Backend.Backend import Backend
 from UM.Application import Application
 from UM.Scene.SceneNode import SceneNode
-from UM.Scene.Iterator.DepthFirstIterator import DepthFirstIterator
 from UM.Preferences import Preferences
-from UM.Math.Vector import Vector
 from UM.Signal import Signal
 from UM.Logger import Logger
 from UM.Qt.Bindings.BackendProxy import BackendState #To determine the state of the slicing job.
-from UM.Resources import Resources
-from UM.Settings.SettingOverrideDecorator import SettingOverrideDecorator
 from UM.Message import Message
 from UM.PluginRegistry import PluginRegistry
 
-from cura.OneAtATimeIterator import OneAtATimeIterator
 from . import ProcessSlicedObjectListJob
 from . import ProcessGCodeJob
 from . import StartSliceJob
 
 import os
 import sys
-import numpy
 
 from PyQt5.QtCore import QTimer
 
diff --git a/plugins/CuraEngineBackend/ProcessSlicedObjectListJob.py b/plugins/CuraEngineBackend/ProcessSlicedObjectListJob.py
index df2e5966e96..6bd8d165b3a 100644
--- a/plugins/CuraEngineBackend/ProcessSlicedObjectListJob.py
+++ b/plugins/CuraEngineBackend/ProcessSlicedObjectListJob.py
@@ -16,7 +16,6 @@
 from cura import LayerDataDecorator
 
 import numpy
-import struct
 
 catalog = i18nCatalog("cura")
 
@@ -51,7 +50,7 @@ def run(self):
 
         object_id_map = {}
         new_node = SceneNode()
-        ## Put all nodes in a dict identified by ID
+        ## Put all nodes in a dictionary identified by ID
         for node in DepthFirstIterator(self._scene.getRoot()):
             if type(node) is SceneNode and node.getMeshData():
                 if node.callDecoration("getLayerData"):
@@ -74,15 +73,15 @@ def run(self):
             layer_count += self._message.getRepeatedMessage("objects", i).repeatedMessageCount("layers")
 
         current_layer = 0
-        for i in range(self._message.repeatedMessageCount("objects")):
-            object = self._message.getRepeatedMessage("objects", i)
+        for object_position in range(self._message.repeatedMessageCount("objects")):
+            current_object = self._message.getRepeatedMessage("objects", object_position)
             try:
-                node = object_id_map[object.id]
+                node = object_id_map[current_object.id]
             except KeyError:
                 continue
 
-            for l in range(object.repeatedMessageCount("layers")):
-                layer = object.getRepeatedMessage("layers", l)
+            for l in range(current_object.repeatedMessageCount("layers")):
+                layer = current_object.getRepeatedMessage("layers", l)
 
                 layer_data.addLayer(layer.id)
                 layer_data.setLayerHeight(layer.id, layer.height)
diff --git a/plugins/CuraEngineBackend/StartSliceJob.py b/plugins/CuraEngineBackend/StartSliceJob.py
index 7c35bca36b8..098808dbfe1 100644
--- a/plugins/CuraEngineBackend/StartSliceJob.py
+++ b/plugins/CuraEngineBackend/StartSliceJob.py
@@ -87,11 +87,11 @@ def run(self):
             group_message = slice_message.addRepeatedMessage("object_lists")
             if group[0].getParent().callDecoration("isGroup"):
                 self._handlePerObjectSettings(group[0].getParent(), group_message)
-            for object in group:
-                mesh_data = object.getMeshData().getTransformed(object.getWorldTransformation())
+            for current_object in group:
+                mesh_data = current_object.getMeshData().getTransformed(current_object.getWorldTransformation())
 
                 obj = group_message.addRepeatedMessage("objects")
-                obj.id = id(object)
+                obj.id = id(current_object)
 
                 verts = numpy.array(mesh_data.getVertices())
                 verts[:,[1,2]] = verts[:,[2,1]]
@@ -99,7 +99,7 @@ def run(self):
 
                 obj.vertices = verts
 
-                self._handlePerObjectSettings(object, obj)
+                self._handlePerObjectSettings(current_object, obj)
 
                 Job.yieldThread()
 
diff --git a/plugins/CuraProfileReader/CuraProfileReader.py b/plugins/CuraProfileReader/CuraProfileReader.py
index 9addec68d2f..e3001da6ae7 100644
--- a/plugins/CuraProfileReader/CuraProfileReader.py
+++ b/plugins/CuraProfileReader/CuraProfileReader.py
@@ -2,6 +2,7 @@
 # Cura is released under the terms of the AGPLv3 or higher.
 
 from UM.Application import Application #To get the machine manager to create the new profile in.
+from UM.Logger import Logger
 from UM.Settings.Profile import Profile
 from UM.Settings.ProfileReader import ProfileReader
 
diff --git a/plugins/CuraProfileWriter/CuraProfileWriter.py b/plugins/CuraProfileWriter/CuraProfileWriter.py
index 479b84f37ed..1ac206e54a2 100644
--- a/plugins/CuraProfileWriter/CuraProfileWriter.py
+++ b/plugins/CuraProfileWriter/CuraProfileWriter.py
@@ -4,7 +4,6 @@
 
 from UM.Logger import Logger
 from UM.SaveFile import SaveFile
-from UM.Settings.Profile import Profile
 from UM.Settings.ProfileWriter import ProfileWriter
 
 ##  Writes profiles to Cura's own profile format with config files.
diff --git a/plugins/GCodeWriter/GCodeWriter.py b/plugins/GCodeWriter/GCodeWriter.py
index 0a76a51742a..e481e4c1877 100644
--- a/plugins/GCodeWriter/GCodeWriter.py
+++ b/plugins/GCodeWriter/GCodeWriter.py
@@ -4,7 +4,6 @@
 from UM.Mesh.MeshWriter import MeshWriter
 from UM.Logger import Logger
 from UM.Application import Application
-import io
 import re #For escaping characters in the settings.
 import copy
 
diff --git a/plugins/ImageReader/ImageReader.py b/plugins/ImageReader/ImageReader.py
index 4aa6a664391..0d6c12b13dd 100644
--- a/plugins/ImageReader/ImageReader.py
+++ b/plugins/ImageReader/ImageReader.py
@@ -1,7 +1,6 @@
 # Copyright (c) 2015 Ultimaker B.V.
 # Cura is released under the terms of the AGPLv3 or higher.
 
-import os
 import numpy
 
 from PyQt5.QtGui import QImage, qRed, qGreen, qBlue
@@ -49,8 +48,8 @@ def read(self, file_name):
         return self._generateSceneNode(file_name, size, self._ui.peak_height, self._ui.base_height, self._ui.smoothing, 512, self._ui.image_color_invert)
 
     def _generateSceneNode(self, file_name, xz_size, peak_height, base_height, blur_iterations, max_size, image_color_invert):
-        mesh = None
-        scene_node = None
+        mesh = None # TODO: @UnusedVariable
+        scene_node = None # TODO: @UnusedVariable
 
         scene_node = SceneNode()
 
@@ -111,7 +110,7 @@ def _generateSceneNode(self, file_name, xz_size, peak_height, base_height, blur_
         if image_color_invert:
             height_data = 1 - height_data
 
-        for i in range(0, blur_iterations):
+        for _ in range(0, blur_iterations):
             copy = numpy.pad(height_data, ((1, 1), (1, 1)), mode= "edge")
 
             height_data += copy[1:-1, 2:]
diff --git a/plugins/LayerView/LayerView.py b/plugins/LayerView/LayerView.py
index eb9c3bc91e7..97a2a0ab305 100644
--- a/plugins/LayerView/LayerView.py
+++ b/plugins/LayerView/LayerView.py
@@ -136,7 +136,7 @@ def setLayer(self, value):
 
     def calculateMaxLayers(self):
         scene = self.getController().getScene()
-        renderer = self.getRenderer() # TODO: Unused variable
+        renderer = self.getRenderer() # TODO: @UnusedVariable
         self._activity = True
 
         self._old_max_layers = self._max_layers
diff --git a/plugins/RemovableDriveOutputDevice/OSXRemovableDrivePlugin.py b/plugins/RemovableDriveOutputDevice/OSXRemovableDrivePlugin.py
index 4b65ce024da..cee4f40430a 100644
--- a/plugins/RemovableDriveOutputDevice/OSXRemovableDrivePlugin.py
+++ b/plugins/RemovableDriveOutputDevice/OSXRemovableDrivePlugin.py
@@ -58,7 +58,7 @@ def _findInTree(self, t, n):
         if type(t) is dict:
             if "_name" in t and t["_name"] == n:
                 ret.append(t)
-            for k, v in t.items():
+            for k, v in t.items(): # TODO: @UnusedVariable "k"
                 ret += self._findInTree(v, n)
         if type(t) is list:
             for v in t:
diff --git a/plugins/RemovableDriveOutputDevice/RemovableDriveOutputDevice.py b/plugins/RemovableDriveOutputDevice/RemovableDriveOutputDevice.py
index f73ba46c85a..3644ae54ca8 100644
--- a/plugins/RemovableDriveOutputDevice/RemovableDriveOutputDevice.py
+++ b/plugins/RemovableDriveOutputDevice/RemovableDriveOutputDevice.py
@@ -8,7 +8,6 @@
 from UM.Scene.Iterator.BreadthFirstIterator import BreadthFirstIterator
 from UM.OutputDevice.OutputDevice import OutputDevice
 from UM.OutputDevice import OutputDeviceError
-from UM.Preferences import Preferences
 
 from UM.i18n import i18nCatalog
 catalog = i18nCatalog("cura")
diff --git a/plugins/RemovableDriveOutputDevice/RemovableDrivePlugin.py b/plugins/RemovableDriveOutputDevice/RemovableDrivePlugin.py
index 1a095e2a687..6ab095f338c 100644
--- a/plugins/RemovableDriveOutputDevice/RemovableDrivePlugin.py
+++ b/plugins/RemovableDriveOutputDevice/RemovableDrivePlugin.py
@@ -4,7 +4,6 @@
 import threading
 import time
 
-from UM.Signal import Signal
 from UM.Message import Message
 from UM.OutputDevice.OutputDevicePlugin import OutputDevicePlugin
 
diff --git a/plugins/RemovableDriveOutputDevice/WindowsRemovableDrivePlugin.py b/plugins/RemovableDriveOutputDevice/WindowsRemovableDrivePlugin.py
index b47a37d35c1..0df38dbf743 100644
--- a/plugins/RemovableDriveOutputDevice/WindowsRemovableDrivePlugin.py
+++ b/plugins/RemovableDriveOutputDevice/WindowsRemovableDrivePlugin.py
@@ -2,21 +2,13 @@
 # Copyright (c) 2013 David Braam
 # Uranium is released under the terms of the AGPLv3 or higher.
 
+from UM.i18n import i18nCatalog
+catalog = i18nCatalog("cura")
+
 from . import RemovableDrivePlugin
 
-import threading
 import string
-
-from ctypes import windll
-from ctypes import wintypes
-
 import ctypes
-import time
-import os
-import subprocess
-
-from UM.i18n import i18nCatalog
-catalog = i18nCatalog("cura")
 
 # WinAPI Constants that we need
 # Hardcoded here due to stupid WinDLL stuff that does not give us access to these values.
@@ -37,7 +29,7 @@ class WindowsRemovableDrivePlugin(RemovableDrivePlugin.RemovableDrivePlugin):
     def checkRemovableDrives(self):
         drives = {}
 
-        bitmask = windll.kernel32.GetLogicalDrives()
+        bitmask = ctypes.windll.kernel32.GetLogicalDrives()
         # Check possible drive letters, from A to Z
         # Note: using ascii_uppercase because we do not want this to change with locale!
         for letter in string.ascii_uppercase:
@@ -45,11 +37,11 @@ def checkRemovableDrives(self):
 
             # Do we really want to skip A and B?
             # GetDriveTypeA explicitly wants a byte array of type ascii. It will accept a string, but this wont work
-            if bitmask & 1 and windll.kernel32.GetDriveTypeA(drive.encode("ascii")) == DRIVE_REMOVABLE:
+            if bitmask & 1 and ctypes.windll.kernel32.GetDriveTypeA(drive.encode("ascii")) == DRIVE_REMOVABLE:
                 volume_name = ""
                 name_buffer = ctypes.create_unicode_buffer(1024)
                 filesystem_buffer = ctypes.create_unicode_buffer(1024)
-                error = windll.kernel32.GetVolumeInformationW(ctypes.c_wchar_p(drive), name_buffer, ctypes.sizeof(name_buffer), None, None, None, filesystem_buffer, ctypes.sizeof(filesystem_buffer))
+                error = ctypes.windll.kernel32.GetVolumeInformationW(ctypes.c_wchar_p(drive), name_buffer, ctypes.sizeof(name_buffer), None, None, None, filesystem_buffer, ctypes.sizeof(filesystem_buffer))
 
                 if error != 0:
                     volume_name = name_buffer.value
@@ -66,7 +58,7 @@ def checkRemovableDrives(self):
 
                 # Check for the free space. Some card readers show up as a drive with 0 space free when there is no card inserted.
                 free_bytes = ctypes.c_longlong(0)
-                if windll.kernel32.GetDiskFreeSpaceExA(drive.encode("ascii"), ctypes.byref(free_bytes), None, None) == 0:
+                if ctypes.windll.kernel32.GetDiskFreeSpaceExA(drive.encode("ascii"), ctypes.byref(free_bytes), None, None) == 0:
                     continue
 
                 if free_bytes.value < 1:
@@ -80,19 +72,19 @@ def checkRemovableDrives(self):
     def performEjectDevice(self, device):
         # Magic WinAPI stuff
         # First, open a handle to the Device
-        handle = windll.kernel32.CreateFileA("\\\\.\\{0}".format(device.getId()[:-1]).encode("ascii"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, None, OPEN_EXISTING, 0, None )
+        handle = ctypes.windll.kernel32.CreateFileA("\\\\.\\{0}".format(device.getId()[:-1]).encode("ascii"), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, None, OPEN_EXISTING, 0, None )
 
         if handle == -1:
-            print(windll.kernel32.GetLastError())
+            print(ctypes.windll.kernel32.GetLastError())
             return
 
         result = None
         # Then, try and tell it to eject
-        if not windll.kernel32.DeviceIoControl(handle, IOCTL_STORAGE_EJECT_MEDIA, None, None, None, None, None, None):
+        if not ctypes.windll.kernel32.DeviceIoControl(handle, IOCTL_STORAGE_EJECT_MEDIA, None, None, None, None, None, None):
             result = False
         else:
             result = True
 
         # Finally, close the handle
-        windll.kernel32.CloseHandle(handle)
+        ctypes.windll.kernel32.CloseHandle(handle)
         return result
diff --git a/plugins/SliceInfoPlugin/SliceInfo.py b/plugins/SliceInfoPlugin/SliceInfo.py
index ed018f7d89f..c2e8b9a147c 100644
--- a/plugins/SliceInfoPlugin/SliceInfo.py
+++ b/plugins/SliceInfoPlugin/SliceInfo.py
@@ -66,7 +66,7 @@ def _onWriteStarted(self, output_device):
                 break
 
 
-        profile_values = settings.getChangedSettings() # TODO: Unused variable
+        profile_values = settings.getChangedSettings() # TODO: @UnusedVariable
 
         # Get total material used (in mm^3)
         print_information = Application.getInstance().getPrintInformation()
diff --git a/plugins/SolidView/SolidView.py b/plugins/SolidView/SolidView.py
index 607455c7b33..8719e9c6e48 100644
--- a/plugins/SolidView/SolidView.py
+++ b/plugins/SolidView/SolidView.py
@@ -5,7 +5,6 @@
 from UM.Scene.Iterator.DepthFirstIterator import DepthFirstIterator
 from UM.Resources import Resources
 from UM.Application import Application
-from UM.Math.Color import Color
 from UM.Preferences import Preferences
 from UM.View.Renderer import Renderer
 
diff --git a/plugins/USBPrinting/PrinterConnection.py b/plugins/USBPrinting/PrinterConnection.py
index d28324b71cc..1e5aa89b42e 100644
--- a/plugins/USBPrinting/PrinterConnection.py
+++ b/plugins/USBPrinting/PrinterConnection.py
@@ -12,10 +12,8 @@
 
 from UM.Application import Application
 from UM.Signal import Signal, SignalEmitter
-from UM.Resources import Resources
 from UM.Logger import Logger
 from UM.OutputDevice.OutputDevice import OutputDevice
-from UM.OutputDevice import OutputDeviceError
 from UM.PluginRegistry import PluginRegistry
 
 from PyQt5.QtQuick import QQuickView
@@ -337,6 +335,7 @@ def close(self):
             try:
                 self._connect_thread.join()
             except Exception as e:
+                Logger.log("d", "PrinterConnection.close: %s (expected)", e)
                 pass # This should work, but it does fail sometimes for some reason
 
         self._connect_thread = threading.Thread(target=self._connect)
@@ -374,7 +373,7 @@ def moveHead(self, x, y, z):
 
     @pyqtSlot()
     def homeHead(self):
-       self._sendCommand("G28")
+        self._sendCommand("G28")
 
     ##  Directly send the command, withouth checking connection state (eg; printing).
     #   \param cmd string with g-code
@@ -457,6 +456,7 @@ def _setExtruderTemperature(self, index, temperature):
             self._extruder_temperatures[index] = temperature
             self.extruderTemperatureChanged.emit()
         except Exception as e:
+            Logger.log("d", "PrinterConnection._setExtruderTemperature: ", e)
             pass
 
     ##  Private function to set the temperature of the bed.
diff --git a/plugins/USBPrinting/USBPrinterManager.py b/plugins/USBPrinting/USBPrinterManager.py
index fbcd6201d77..d6836468abe 100644
--- a/plugins/USBPrinting/USBPrinterManager.py
+++ b/plugins/USBPrinting/USBPrinterManager.py
@@ -4,8 +4,6 @@
 from UM.Signal import Signal, SignalEmitter
 from . import PrinterConnection
 from UM.Application import Application
-from UM.Scene.Iterator.DepthFirstIterator import DepthFirstIterator
-from UM.Scene.SceneNode import SceneNode
 from UM.Resources import Resources
 from UM.Logger import Logger
 from UM.PluginRegistry import PluginRegistry
@@ -20,7 +18,6 @@
 import glob
 import time
 import os.path
-import sys
 from UM.Extension import Extension
 
 from PyQt5.QtQuick import QQuickView
@@ -59,7 +56,7 @@ def __init__(self, parent = None):
     @pyqtProperty(float, notify = progressChanged)
     def progress(self):
         progress = 0
-        for printer_name, connection in self._printer_connections.items():
+        for printer_name, connection in self._printer_connections.items(): # TODO: @UnusedVariable "printer_name"
             progress += connection.progress
 
         return progress / len(self._printer_connections)
@@ -231,6 +228,7 @@ def getSerialPortList(self, only_list_usb = False):
                         base_list += [values[1]]
                     i += 1
             except Exception as e:
+                Logger.log("d", "USBPrinterManager.getSerialPortList: ", e)
                 pass
         else:
             if only_list_usb:
diff --git a/setup.py b/setup.py
index f5b3c3e1061..1eeca36ed66 100644
--- a/setup.py
+++ b/setup.py
@@ -4,10 +4,9 @@
 from distutils.core import setup
 import py2exe
 import UM
-import UM.Qt
-import cura
+import UM.Qt #@UnusedImport
+import cura  #@UnusedImport
 import os
-import re
 import shutil
 import site
 
@@ -74,4 +73,4 @@ def copytree(src, dst, symlinks=False, ignore=None):
         print("Copying Angle libraries from %s" % qt_origin_path)
         shutil.copy(os.path.join(qt_origin_path, "libEGL.dll"), "dist/libEGL.dll")
         shutil.copy(os.path.join(qt_origin_path, "libGLESv2.dll"), "dist/libGLESv2.dll")
-os.rename("dist/cura_app.exe", "dist/Cura.exe")
\ No newline at end of file
+os.rename("dist/cura_app.exe", "dist/Cura.exe")