i tried to upgrade from Ubuntu Mate 15.10 to 16.04 but i get this error message :
ubuntu@ubuntumate:~$ sudo update-manager -d
Checking for a new Ubuntu release
Gtk-Message: GtkDialog mapped without a transient parent. This is discouraged.
java version “1.7.0_95”
OpenJDK Runtime Environment (IcedTea 2.6.4) (7u95-2.6.4-0ubuntu0.15.10.2)
OpenJDK Server VM (build 24.95-b01, mixed mode)
authenticate ‘xenial.tar.gz’ against ‘xenial.tar.gz.gpg’
extracting ‘xenial.tar.gz’
Traceback (most recent call last):
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/xenial”, line 8, in
sys.exit(main())
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/DistUpgrade/DistUpgradeMain.py”, line 229, in main
app = DistUpgradeController(view, options, datadir=options.datadir)
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/DistUpgrade/DistUpgradeController.py”, line 159, in init
self.quirks = DistUpgradeQuirks(self, self.config)
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/DistUpgrade/DistUpgradeQuirks.py”, line 63, in init
self._uid = os.environ[‘SUDO_UID’]
File “/usr/lib/python3.4/os.py”, line 633, in getitem
raise KeyError(key) from None
KeyError: ‘SUDO_UID’
Error in sys.excepthook:
Traceback (most recent call last):
File “/usr/lib/python3/dist-packages/problem_report.py”, line 480, in add_to_existing
self.write(f)
File “/usr/lib/python3/dist-packages/problem_report.py”, line 435, in write
crc = zlib.crc32(block, crc)
TypeError: ‘str’ does not support the buffer interface
Original exception was:
Traceback (most recent call last):
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/xenial”, line 8, in
sys.exit(main())
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/DistUpgrade/DistUpgradeMain.py”, line 229, in main
app = DistUpgradeController(view, options, datadir=options.datadir)
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/DistUpgrade/DistUpgradeController.py”, line 159, in init
self.quirks = DistUpgradeQuirks(self, self.config)
File “/tmp/ubuntu-release-upgrader-2_7u7qq5/DistUpgrade/DistUpgradeQuirks.py”, line 63, in init
self._uid = os.environ[‘SUDO_UID’]
File “/usr/lib/python3.4/os.py”, line 633, in getitem
raise KeyError(key) from None
KeyError: ‘SUDO_UID’