When I was updating suddenly the process aborted with the message:
Could not calculate the upgrade An unresolvable problem occurred while calculating the upgrade. This was likely caused by: * Unofficial software packages not provided by Ubuntu Please use the tool 'ppa-purge' from the ppa-purge package to remove software from a Launchpad PPA and try the upgrade again. If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If you want to investigate this yourself the log files in '/var/log/dist-upgrade' will contain details about the upgrade. Specifically, look at 'main.log' and 'apt.log'. Restoring original system state Aborting Reading package lists... Done Building dependency tree Reading state information... Done
Please help me with update to Ubuntu 20.04 from 18.04.