I ran into this problem after installing the Opera web browser on Linux Mint. Srsly, just don't go there. I'm not sure what the guise who let the present Opera package into the repos were smoking, but apparently they did not test it against older but still living LTS (Long Term Support) versions of "supported" Debian-based operating systems before doing so.
If this ever happens to a system you're in charge of - update attempts returning "error code 1" and no changes made because of broken junk - here's a simple fix that works. Pop open a terminal and do:
This gets you to the directory where dpkg stores its configuration files related to installed software. Then do:
ls | grep -i opera
(replace "opera" with whatever package broke your package manager)
This command lists every file with "Opera" or etc. in its name. Look them over: Is anything /not/ related to Opera (or whatever) listed? If so, take note and delete only the "offending" package's files one at a time, using their full names, to avoid breaking other things with similar names. But if all the returns from your search obviously belong to the borken package, do:
sudo rm opera
... replacing "opera" with whatever junk has disabled your package manager.
Result: The half-installed broken package will sit on your hard drive "forever", an Mortal Insult to All That Is Good And Holy - but doing no actual harm of any kind other than wasting a few MB of drive space. Unless you go into you /bin directory and remove them by hand. Either way, you can now update your installed software, install new packages, etc. normally, because your package manager no longer knows that the failed package and its borken parts ever existed.