Merge branch 'master' of github.com:Ultimaker/Cura

plugins/3MFWriter/ThreeMFWorkspaceWriter.py

@@ -63,7 +63,7 @@ class ThreeMFWorkspaceWriter(WorkspaceWriter):
         # Write preferences to archive
         original_preferences = Application.getInstance().getPreferences() #Copy only the preferences that we use to the workspace.
         temp_preferences = Preferences()
-        for preference in {"general/visible_settings", "cura/active_mode", "cura/categories_expanded"}:
+        for preference in {"general/visible_settings", "cura/active_mode", "cura/categories_expanded", "metadata/setting_version"}:
             temp_preferences.addPreference(preference, None)
             temp_preferences.setValue(preference, original_preferences.getValue(preference))
         preferences_string = StringIO()

plugins/USBPrinting/USBPrinterOutputDeviceManager.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2018 Ultimaker B.V.
+# Copyright (c) 2020 Ultimaker B.V.
 # Cura is released under the terms of the LGPLv3 or higher.
 
 import threading
@@ -117,6 +117,8 @@ class USBPrinterOutputDeviceManager(QObject, OutputDevicePlugin):
         for port in serial.tools.list_ports.comports():
             if not isinstance(port, tuple):
                 port = (port.device, port.description, port.hwid)
+            if not port[2]:  # HWID may be None if the port got disconnected while processing.
+                continue
             if only_list_usb and not port[2].startswith("USB"):
                 continue