Dist-upgrade from Ubuntu 14.04 to Ubuntu 16.04.1 fails to update MySQL 5.5:
Errors were encountered while processing:
E: Sub-process /usr/bin/dpkg returned an error code (1)
Plesk bug with ID #PPPM-7431 fixed in Plesk Obsidian on February 12, 2019 (fixed as PPP-33523, Linux).
For Plesk Obsidian, install the latest Plesk micro-updates.
For Plesk Onyx, upgrade to the latest Plesk version.
If update is not possible for some reason, try the following
1. Login to Plesk server over SSH
and comment out two parameters:
3. Restart MySQL service:
# service mysql restart
4. Complete the failed upgrade:
# apt-get -f install