我实际上是在一家公司实习，所以他们要求我在开始工作之前更新他们的 Ubuntu。问题是，当我执行“ do-release-upgrade”时，我收到一条错误消息，系统恢复到原始状态。然后我检查了 main.log，发现有以下几行：
2019-07-03 09:34:48,879 INFO Using config files '['./DistUpgrade.cfg.trusty']'
2019-07-03 09:34:48,879 INFO uname information: 'Linux AWARE 3.16.0-30-generic #40~14.04.1-Ubuntu SMP Thu Jan 15 17:43:14 UTC 2015 x86_64'
2019-07-03 09:34:49,431 INFO apt version: '1.0.1ubuntu2.23'
2019-07-03 09:34:49,431 INFO python version: '3.4.3 (default, Nov 12 2018, 22:25:49)
[GCC 4.8.4]'
2019-07-03 09:34:49,436 INFO release-upgrader version '16.04.26' started
2019-07-03 09:34:49,445 INFO locale: 'fr_FR' 'UTF-8'
2019-07-03 09:34:49,459 DEBUG screen returned: 'No Sockets found in /var/run/screen/S-root. 2019-07-03 09:34:49,460 INFO re-exec inside screen: '['screen', '-e', '\\0\\0', '-L', '-c', 'screenrc', '-S', 'ubuntu-release-upgrade-screen-window', '/tmp/ubuntu-release-upgrader-p0eywysq/xenial', '--mode=server', '--frontend=DistUpgradeViewText']'