diff --git a/qubesmanager/backup.py b/qubesmanager/backup.py
index 97a02d9..320571c 100644
--- a/qubesmanager/backup.py
+++ b/qubesmanager/backup.py
@@ -357,9 +357,15 @@ class BackupVMsWindow(ui_backupdlg.Ui_Backup, QtWidgets.QWizard):
     def reject(self):
         if (self.currentPage() is self.commit_page) and \
                 self.button(self.CancelButton).isEnabled():
-            self.qubes_app.qubesd_call(
-                'dom0', 'admin.backup.Cancel',
-                backup_utils.get_profile_name(True))
+            try:
+                self.qubes_app.qubesd_call(
+                    'dom0', 'admin.backup.Cancel',
+                    backup_utils.get_profile_name(True))
+            except exc.QubesException as ex:
+                QtWidgets.QMessageBox.warning(
+                    self, self.tr("Error cancelling backup!"),
+                    self.tr("ERROR: {}").format(str(ex)))
+
             self.thread.wait()
             QtWidgets.QMessageBox.warning(
                 self, self.tr("Backup aborted!"),
diff --git a/qubesmanager/tests/test_vm_settings.py b/qubesmanager/tests/test_vm_settings.py
index 646116f..f9fc96f 100644
--- a/qubesmanager/tests/test_vm_settings.py
+++ b/qubesmanager/tests/test_vm_settings.py
@@ -58,24 +58,28 @@ class VMSettingsTest(unittest.TestCase):
         self.assertTrue(
             self.dialog.tabWidget.currentWidget() is self.dialog.basic_tab)
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="advanced")
         self.assertTrue(
             self.dialog.tabWidget.currentWidget() is self.dialog.advanced_tab)
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="firewall")
         self.assertTrue(
             self.dialog.tabWidget.currentWidget() is self.dialog.firewall_tab)
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="devices")
         self.assertTrue(
             self.dialog.tabWidget.currentWidget() is self.dialog.devices_tab)
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp,
@@ -83,12 +87,14 @@ class VMSettingsTest(unittest.TestCase):
         self.assertTrue(
             self.dialog.tabWidget.currentWidget() is self.dialog.apps_tab)
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="services")
         self.assertTrue(
             self.dialog.tabWidget.currentWidget() is self.dialog.services_tab)
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
     def test_01_basic_tab_default(self):
         self.vm = self.qapp.add_new_vm("AppVM", "test-vm", "blue")
@@ -405,6 +411,7 @@ class VMSettingsTest(unittest.TestCase):
         self.assertEqual(self.vm.maxmem, 0)
 
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="advanced")
@@ -457,6 +464,7 @@ class VMSettingsTest(unittest.TestCase):
         self.assertEqual(self.vm.kernel, new_kernel)
 
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="advanced")
@@ -482,6 +490,7 @@ class VMSettingsTest(unittest.TestCase):
             self.assertEqual(self.vm.virt_mode.upper(), mode)
 
             self.dialog.deleteLater()
+            self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="advanced")
@@ -502,6 +511,7 @@ class VMSettingsTest(unittest.TestCase):
         self.assertEqual(self.vm.default_dispvm.name, new_dvm)
 
         self.dialog.deleteLater()
+        self.qtapp.processEvents()
 
         self.dialog = vm_settings.VMSettingsWindow(
             self.vm, qapp=self.qtapp, qubesapp=self.qapp, init_page="advanced")