Found the problem!
Looking at the processes running at the upgrade, there is - my root shell, PATH is ok - /bin/sh -c /usr/bin/pkexec /usr/bin/do-release-upgrade --frontend=DIstUpgradeViewGtk3 -d PATH is ok - /usr/bin/python3 /tmp/ubuntu-... --mode=server --frontend=... PATH is broken : /usr/local/bin:/usr/bin:/bin:/sbin lacks /usr/sbin and it is definitely the pkexec call. running pkexec env as root shows the broken PATH. Which finally shows the Problem: /usr/sbin was missing in the PATH variable in /etc/environment. The update process should *urgently* take care to have a complete PATH. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1544904 Title: Updating 15.10 to 16.04 alpha2 failed: subprocess exit status 127 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1544904/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
