diff --git a/qubesmanager.pro b/qubesmanager.pro
index 51f4d1c..f186c52 100644
--- a/qubesmanager.pro
+++ b/qubesmanager.pro
@@ -17,6 +17,7 @@ SOURCES = \
           qubesmanager/block.py \
           qubesmanager/clipboard.py \
           qubesmanager/create_new_vm.py \
+          qubesmanager/common_threads.py \
           qubesmanager/firewall.py \
           qubesmanager/global_settings.py \
           qubesmanager/log_dialog.py \
@@ -27,7 +28,6 @@ SOURCES = \
           qubesmanager/restore.py \
           qubesmanager/settings.py \
           qubesmanager/table_widgets.py \
-          qubesmanager/thread_monitor.py \
           qubesmanager/ui_about.py \
           qubesmanager/ui_backupdlg.py \
           qubesmanager/ui_globalsettingsdlg.py \
diff --git a/qubesmanager/backup.py b/qubesmanager/backup.py
index 9847c9c..542df22 100644
--- a/qubesmanager/backup.py
+++ b/qubesmanager/backup.py
@@ -44,7 +44,6 @@ import sys
 import os
 import asyncio
 from contextlib import suppress
-import time
 
 class BackupThread(QtCore.QThread):
     def __init__(self, vm):
@@ -76,6 +75,7 @@ class BackupVMsWindow(ui_backupdlg.Ui_Backup, multiselectwidget.QtGui.QWizard):
         self.backup_settings = QtCore.QSettings()
 
         self.selected_vms = []
+        self.thread = None
 
         self.setupUi(self)
 
diff --git a/qubesmanager/common_threads.py b/qubesmanager/common_threads.py
index c7fd1ff..746f9ea 100644
--- a/qubesmanager/common_threads.py
+++ b/qubesmanager/common_threads.py
@@ -42,10 +42,11 @@ class CloneVMThread(QtCore.QThread):
         QtCore.QThread.__init__(self)
         self.src_vm = src_vm
         self.dst_name = dst_name
+        self.error = None
 
     def run(self):
         try:
-            dst_vm = self.src_vm.app.clone_vm(self.src_vm, self.dst_name)
+            self.src_vm.app.clone_vm(self.src_vm, self.dst_name)
             self.error = ("Sucess", "The qube was cloned sucessfully.")
         except exc.QubesException as ex:
             self.error = ("Error while cloning Qube!", str(ex))
diff --git a/qubesmanager/create_new_vm.py b/qubesmanager/create_new_vm.py
index 73959ad..88122c3 100644
--- a/qubesmanager/create_new_vm.py
+++ b/qubesmanager/create_new_vm.py
@@ -22,8 +22,6 @@
 #
 
 import sys
-import threading
-import time
 import subprocess
 
 from PyQt4 import QtCore, QtGui  # pylint: disable=import-error
@@ -78,6 +76,9 @@ class NewVmDlg(QtGui.QDialog, Ui_NewVMDlg):
         self.qtapp = qtapp
         self.app = app
 
+        self.thread = None
+        self.progress = None
+
         # Theoretically we should be locking for writing here and unlock
         # only after the VM creation finished. But the code would be
         # more messy...
@@ -174,7 +175,7 @@ class NewVmDlg(QtGui.QDialog, Ui_NewVMDlg):
         if self.thread.error:
             QtGui.QMessageBox.warning(None,
                 self.tr("Error creating the qube!"),
-                self.tr("ERROR: {}").format(thread.error))
+                self.tr("ERROR: {}").format(self.thread.error))
 
         self.done(0)
 
@@ -183,7 +184,7 @@ class NewVmDlg(QtGui.QDialog, Ui_NewVMDlg):
                 subprocess.check_call(['qubes-vm-settings', str(self.name)])
             if self.install_system.isChecked():
                 subprocess.check_call(
-                    ['qubes-vm-boot-from-device', srt(self.name)])
+                    ['qubes-vm-boot-from-device', str(self.name)])
 
 
     def type_change(self):
diff --git a/qubesmanager/qube_manager.py b/qubesmanager/qube_manager.py
index ef9e495..25ea5d3 100644
--- a/qubesmanager/qube_manager.py
+++ b/qubesmanager/qube_manager.py
@@ -28,7 +28,6 @@ import subprocess
 from datetime import datetime, timedelta
 import traceback
 from contextlib import suppress
-import time
 
 import quamash
 import asyncio
@@ -282,6 +281,7 @@ class RunCommandThread(QtCore.QThread):
         QtCore.QThread.__init__(self)
         self.vm = vm
         self.command_to_run = command_to_run
+        self.error = None
 
     def run(self):
         try:
@@ -450,7 +450,8 @@ class VmManagerWindow(ui_qubemanager.Ui_VmManagerWindow, QtGui.QMainWindow):
         dispatcher.add_handler('domain-start-failed',
                                self.on_domain_status_changed)
         dispatcher.add_handler('domain-stopped', self.on_domain_status_changed)
-        dispatcher.add_handler('domain-pre-shutdown', self.on_domain_status_changed)
+        dispatcher.add_handler('domain-pre-shutdown',
+                                self.on_domain_status_changed)
         dispatcher.add_handler('domain-shutdown', self.on_domain_status_changed)
         dispatcher.add_handler('domain-paused', self.on_domain_status_changed)
         dispatcher.add_handler('domain-unpaused', self.on_domain_status_changed)
@@ -777,7 +778,8 @@ class VmManagerWindow(ui_qubemanager.Ui_VmManagerWindow, QtGui.QMainWindow):
             # remove the VM
             thread = common_threads.RemoveVMThread(vm)
             self.threads_list.append(thread)
-            self.connect(thread, QtCore.SIGNAL("show_error(QString, QString)"), self.show_error)
+            self.connect(thread, QtCore.SIGNAL("show_error(QString, QString)"),
+                            self.show_error)
             thread.finished.connect(self.clear_threads)
             thread.start()
 
@@ -803,7 +805,6 @@ class VmManagerWindow(ui_qubemanager.Ui_VmManagerWindow, QtGui.QMainWindow):
                 "Cloning Qube..."), "", 0, 0)
         self.progress.setCancelButton(None)
         self.progress.setModal(True)
-        self.thread_closes = True
         self.progress.show()
 
         thread = common_threads.CloneVMThread(vm, clone_name)
@@ -871,7 +872,7 @@ class VmManagerWindow(ui_qubemanager.Ui_VmManagerWindow, QtGui.QMainWindow):
             self.tr("Are you sure you want to power down the Qube"
                     " <b>'{0}'</b>?<br><small>This will shutdown all the "
                     "running applications within this Qube.</small>").format(
-                        vm.name), QtGui.QMessageBox.Yes | QtGui.QMessageBox.Cancel)
+                     vm.name), QtGui.QMessageBox.Yes | QtGui.QMessageBox.Cancel)
 
         self.qt_app.processEvents()
 
diff --git a/qubesmanager/restore.py b/qubesmanager/restore.py
index 985e346..6cb46c7 100644
--- a/qubesmanager/restore.py
+++ b/qubesmanager/restore.py
@@ -23,8 +23,6 @@
 import sys
 from PyQt4 import QtCore  # pylint: disable=import-error
 from PyQt4 import QtGui  # pylint: disable=import-error
-import threading
-import time
 import os
 import os.path
 import traceback
@@ -39,7 +37,7 @@ from . import ui_restoredlg  # pylint: disable=no-name-in-module
 from . import multiselectwidget
 from . import backup_utils
 
-from multiprocessing import Queue, Event
+from multiprocessing import Queue
 from multiprocessing.queues import Empty
 from qubesadmin import Qubes, exc
 from qubesadmin.backup import restore
@@ -52,6 +50,7 @@ class RestoreThread(QtCore.QThread):
         self.vms_to_restore = vms_to_restore
         self.error = None
         self.msg = None
+        self.canceled = None
 
     def run(self):
         err_msg = []
@@ -85,6 +84,9 @@ class RestoreVMsWindow(ui_restoredlg.Ui_Restore, QtGui.QWizard):
         self.vms_to_restore = None
         self.func_output = []
 
+        self.thread = None
+        self.old_sigchld_handler = None
+
         # Set up logging
         self.feedback_queue = Queue()
         handler = logging.handlers.QueueHandler(self.feedback_queue)
@@ -206,13 +208,14 @@ class RestoreVMsWindow(ui_restoredlg.Ui_Restore, QtGui.QWizard):
                                            and str(self.dir_line_edit.text())
                                            .count("media/") > 0)
 
-            self.thread = RestoreThread(self.backup_restore, self.vms_to_restore)
+            self.thread = RestoreThread(self.backup_restore,
+                                        self.vms_to_restore)
             self.thread.finished.connect(self.thread_finished)
 
             # Start log timer
             timer = QtCore.QTimer(self)
             timer.timeout.connect(self.update_log)
-            timer.start(1000) 
+            timer.start(1000)
 
             self.thread.start()
 
diff --git a/qubesmanager/settings.py b/qubesmanager/settings.py
index 51b697d..742cc8e 100755
--- a/qubesmanager/settings.py
+++ b/qubesmanager/settings.py
@@ -28,8 +28,6 @@ import os.path
 import os
 import re
 import subprocess
-import threading
-import time
 import traceback
 import sys
 from qubesadmin.tools import QubesArgumentParser
@@ -85,9 +83,9 @@ class RenameVMThread(QtCore.QThread):
                             "To resolve this, please check and change the "
                             "following properties and remove the qube {} "
                             "manually.<br> ").format(
-                                self.vm.name, name, self.vm.name) + list_text)
+                                self.vm.name, self.vm.name, self.vm.name) + list_text)
 
-        except exc.QubesException as qex:
+        except exc.QubesException as ex:
             self.error = ("Rename error!", str(ex))
         except Exception as ex:  # pylint: disable=broad-except
             self.error = ("Rename error!", repr(ex))
@@ -117,7 +115,7 @@ class RefreshAppsVMThread(QtCore.QThread):
             if not_running:
                 target_vm.shutdown()
 
-        except Exception as ex:
+        except Exception as ex:  # pylint: disable=broad-except
             self.error = ("Refresh failed!", str(ex))
 
 
@@ -265,7 +263,7 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
                 self,
                 self.tr("Error while changing settings for {0}!"
                         ).format(self.vm.name),
-                self.tr("ERROR: {0}").format('\n'.join(ret)))
+                self.tr("ERROR: {0}").format('\n'.join(error)))
 
     def apply(self):
         self.save_changes()
@@ -564,7 +562,7 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
         if ok:
             thread = RenameVMThread(self.vm, new_vm_name, dependencies)
             self.threads_list.append(thread)
-            thread.finished.connect(self.clear_threads) 
+            thread.finished.connect(self.clear_threads)
 
             self.progress = QtGui.QProgressDialog(
                 self.tr(
@@ -621,7 +619,7 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
 
         if ok:
             thread = common_threads.CloneVMThread(self.vm, cloned_vm_name)
-            thread.finished.connect(self.clear_threads) 
+            thread.finished.connect(self.clear_threads)
             self.threads_list.append(thread)
 
             self.progress = QtGui.QProgressDialog(
@@ -966,8 +964,8 @@ class VMSettingsWindow(ui_settingsdlg.Ui_SettingsDialog, QtGui.QDialog):
         self.refresh_apps_button.setText(self.tr('Refresh in progress...'))
 
         thread = RefreshAppsVMThread(self.vm)
-        thread.finished.connect(self.clear_threads) 
-        thread.finished.connect(self.refresh_finished) 
+        thread.finished.connect(self.clear_threads)
+        thread.finished.connect(self.refresh_finished)
         self.threads_list.append(thread)
         thread.start()