I tried changing the mirror several times, as suggested in other forum topics, where I get "Failed to Download Package Files".
It fails to download at random times, no matter what the server is; but it never succeeds at updating a thing. Sometimes many files will download, and it suddenly trips. It's like a clumsy super-fast sprinter, and you're not sure when he's going to hit the dirt; but he always does.
Also of note. I can use the browser on the same machine (I am right now) with no connection issues, save for Firefox failing to restore previous windows on launch.
These are the results of the commands suggested in this troubleshooting guide [ https://help.ubuntu.com/community/PackageManagerTroubleshootingProcedure ] :
:~$ ubuntu-support-status
Support status summary of 'christopher-elitedesk':
You have 1489 packages (81.5%) supported until July 2020 (Canonical - 9m)
You have 0 packages (0.0%) that can not/no-longer be downloaded
You have 339 packages (18.5%) that are unsupported
:~$ cat /etc/dpkg/dpkg.cfg.d/multiarch
cat: /etc/dpkg/dpkg.cfg.d/multiarch: No such file or directory
:~$ dpkg --print-foreign-architectures
i386
:~$ sudo grep -R roxy /etc/apt/*
[no output from this command. Checked "which roxy"... nothing. Skipping roxy commands.]
:~$ echo $http_proxy
[blank line returned]
:~$ echo $ftp_proxy
[blank line returned]
:~$ cat /etc/apt/apt.conf
cat: /etc/apt/apt.conf: No such file or directory
sudo fuser -vvv /var/lib/dpkg/lock
[nothing returned but "which fuser" returns an executable]
:~$ sudo fuser -vvv /var/cache/apt/archives/lock
[nothing returned]
:~$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=19.10
DISTRIB_CODENAME=eoan
DISTRIB_DESCRIPTION="Ubuntu 19.10"
:~$ uname -a
Linux [my computer's name removed for privacy] 5.3.0-18-generic #19-Ubuntu SMP Tue Oct 8 20:14:06 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
:~$ sudo rm /var/lib/apt/lists/lock
[nothing returned]
:~$ sudo rm /var/cache/apt/archives/lock
[nothing returned]
:~$ sudo rm /var/lib/dpkg/lock
[nothing returned]
;~$ sudo cp -arf /var/lib/dpkg /var/lib/dpkg.backup
[These commands are now officially creeping me out--seem pretty aimless. I did not execute the above or the remainder. Let me know if there's a command I should run for more info....]