diff --git a/plugins/CuraEngineBackend/CuraEngineBackend.py b/plugins/CuraEngineBackend/CuraEngineBackend.py
index e55abe59a2..401ed71347 100755
--- a/plugins/CuraEngineBackend/CuraEngineBackend.py
+++ b/plugins/CuraEngineBackend/CuraEngineBackend.py
@@ -119,6 +119,7 @@ class CuraEngineBackend(QObject, Backend):
         self._postponed_scene_change_sources = []  # scene change is postponed (by a tool)
 
         self._slice_start_time = None
+        self._is_disabled = False
 
         Preferences.getInstance().addPreference("general/auto_slice", True)
 
@@ -405,6 +406,7 @@ class CuraEngineBackend(QObject, Backend):
     #   - decorator isBlockSlicing is found (used in g-code reader)
     def determineAutoSlicing(self):
         enable_timer = True
+        self._is_disabled = False
 
         if not Preferences.getInstance().getValue("general/auto_slice"):
             enable_timer = False
@@ -412,6 +414,7 @@ class CuraEngineBackend(QObject, Backend):
             if node.callDecoration("isBlockSlicing"):
                 enable_timer = False
                 self.backendStateChange.emit(BackendState.Disabled)
+                self._is_disabled = True
             gcode_list = node.callDecoration("getGCodeList")
             if gcode_list is not None:
                 self._scene.gcode_dict[node.callDecoration("getBuildPlateNumber")] = gcode_list
@@ -524,6 +527,9 @@ class CuraEngineBackend(QObject, Backend):
 
     ##  Convenient function: mark everything to slice, emit state and clear layer data
     def needsSlicing(self):
+        self.determineAutoSlicing()
+        if self._is_disabled:
+            return
         self.stopSlicing()
         self.markSliceAll()
         self.processingProgress.emit(0.0)
diff --git a/plugins/PluginBrowser/PluginBrowser.py b/plugins/PluginBrowser/PluginBrowser.py
index c8a5e1e545..bb4d5fb395 100644
--- a/plugins/PluginBrowser/PluginBrowser.py
+++ b/plugins/PluginBrowser/PluginBrowser.py
@@ -1,11 +1,10 @@
 # Copyright (c) 2017 Ultimaker B.V.
 # PluginBrowser is released under the terms of the LGPLv3 or higher.
 
-from PyQt5.QtCore import QUrl, QObject, Qt, pyqtProperty, pyqtSignal, pyqtSlot
+from PyQt5.QtCore import QUrl, QObject, pyqtProperty, pyqtSignal, pyqtSlot
 from PyQt5.QtNetwork import QNetworkAccessManager, QNetworkRequest, QNetworkReply
 
 from UM.Application import Application
-from UM.Qt.ListModel import ListModel
 from UM.Logger import Logger
 from UM.PluginRegistry import PluginRegistry
 from UM.Qt.Bindings.PluginsModel import PluginsModel
@@ -20,7 +19,6 @@ import os
 import tempfile
 import platform
 import zipfile
-import shutil
 
 from cura.CuraApplication import CuraApplication
 
@@ -44,7 +42,7 @@ class PluginBrowser(QObject, Extension):
         self._plugins_metadata = []
         self._plugins_model = None
 
-        # Can be 'installed' or 'availble'
+        # Can be 'installed' or 'available'
         self._view = "available"
 
         self._restart_required = False