Hi Melissa I'll firstly provide the following official wiki page https://help.ubuntu.com/community/CleanUpgrade
The error message mentions the tool `ppa-purge` which is probably easiest if you read a support site like https://askubuntu.com/questions/307/how-can-ppas-be-removed, though other Ubuntu wiki pages have examples too - - https://help.ubuntu.com/community/UbuntuStudio/BackportsPPA - https://wiki.ubuntu.com/UbuntuGNOME/HowTo/UpgradeGnomeShell You'll have to know the names of the PPAs you added; looking in your sources, or `history` can provide clues. If you need support, please have a look at https://discourse.ubuntu.com/t/finding-help/712 (if this bug report is converted into a question it'll convert to the last option in the list on that page). -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1840386 Title: impossible calculate upgrade of version To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-release-upgrader/+bug/1840386/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
