I finally found the cause of the problem! It seems that the DBus service (or the whole DBus) is not running in a UTF-8 locale, thus causing errors in UTF-8 strings.
The workaround is to edit softwareproperties/SoftwareProperties.py and add: path = path.encode('utf-8') in method "def add_key(self, path)" around line 800 before the line: if not os.path.exists(path): This encoding issue may be causing problems in other parts of the program, and other programs. Meanwhile, I found another bug: Dragging and dropping a key file to the list doesn't work, raising an exception: Traceback (most recent call last): File "/usr/lib/python3/dist-packages/softwareproperties/gtk/SoftwarePropertiesGtk.py", line 759, in on_auth_drag_data_received keydata = selection.data.strip() AttributeError: 'SelectionData' object has no attribute 'data' -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to software-properties in Ubuntu. https://bugs.launchpad.net/bugs/1381050 Title: "Import Key File" fails when the path of the file has special characters Status in “software-properties” package in Ubuntu: New Bug description: The "Import Key File..." button in the "Authentication" tab fails silently when the path of the selected key file includes special characters. I'm using Ubuntu in Portuguese, so the "/home/$USER/Downloads" folder is named "/home/$USER/Transferências" here. Adding a key from that folder fails, but adding a key from "/home/$USER" (no special characters) succeeds. The problem is that, in softwareproperties/gtk/SoftwarePropertiesGtk.py in method SoftwarePropertiesGtk.add_key_clicked() at around line 952: if res == Gtk.ResponseType.ACCEPT: try: if not self.backend.AddKey(chooser.get_filename()): error(self.window_main, _("Error importing selected file"), _("The selected file may not be a GPG key file " "or it might be corrupt.")) except dbus.DBusException as e: if e._dbus_error_name == 'com.ubuntu.SoftwareProperties.PermissionDeniedByPolicy': logging.error("Authentication canceled, changes have not been saved") "self.backend.AddKey(chooser.get_filename())" throws a "org.freedesktop.DBus.Python.UnicodeEncodeError" exception for paths with special characters. This is probably a side effect of switching from Python 2 to 3 (and 'bytes' now being used in network communications where 'str' was previously used). Another issue is that the error isn't reported to the user, and it should be. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: software-properties-gtk 0.92.37.1 ProcVersionSignature: Ubuntu 3.13.0-37.64-generic 3.13.11.7 Uname: Linux 3.13.0-37-generic x86_64 ApportVersion: 2.14.1-0ubuntu3.5 Architecture: amd64 CurrentDesktop: Unity Date: Tue Oct 14 13:22:21 2014 EcryptfsInUse: Yes InstallationDate: Installed on 2014-10-13 (0 days ago) InstallationMedia: Ubuntu 14.04.1 LTS "Trusty Tahr" - Release amd64 (20140722.2) PackageArchitecture: all SourcePackage: software-properties UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/software-properties/+bug/1381050/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp