Can't upgrade Ubuntu 18.04 to 20.04

[oldfred]

This shows a very basic sources list for bionic, back up first as shown.
reset /etc/apt/sources.list to bionic
https://ubuntuforums.org/showthread....0#post13843080

Then change from bionic to focal
Change distribution. using find to replace in sources
#sudo sed -i 's/find/replace/g' /etc/apt/sources.list
sudo sed -i 's/bionic/focal/g' /etc/apt/sources.list

[readableauthor]

It's not a proper way to update your system oldfred

[oldfred]

While not the recommended way, we have an issue where sources are all mixed up & need to be fixed.
My suggestion for correct way is almost always, new clean install & restore from backups. But too many users do not even have any backup.

[kubasienczyk]

@oldfred Thanks. Let me clear the procedure up:

1: back up the sources.list doc
2: move it elsewhere (can it be done with GUI?)
3: create a new sources.list file with the linked terminal command
4: inside the sources.list file, replace each "bionic" entry with "focal"
5: sudo apt-get update > sudo apt-get upgrade > Software Updater > Upgrade

Is the above correct?

[readableauthor]

Is the above correct?

No, this will mess your system up.

Do the following:
1. Restore default /etc/apt/sources.list from here:
https://gist.github.com/rhuancarlos/...dca8edf1e76800
2. Update the APT caches:

sudo apt update

3. Delete all your PPAs using this answer:
https://askubuntu.com/a/646918/1592865
4. Run the GUI updater tool.

[oldfred]

The link above I think is really the same, just with all the normal comments whcih are not processed as they have # as first char.

[kubasienczyk]

I would like to sincerely thank everyone who provided their insights on the matter. I was eventually able to upgrade 18.04 to 20.04 on both machines. @readableauthor's instructions were spot on and solved my problem.

Thank you!