apt-get upgrade fails: "guvcview : Depends: libguvcview-2.0-0 but it is not installed" [duplicate]

EDIT: My question is a duplicate but my answer here is a bit different than the answer in the linked duplicate above.

I cannot install, remove, or upgrade anything using APT because of this error:

$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 guvcview : Depends: libguvcview-2.0-0 but it is not installed
            Recommends: uvcdynctrl but it is not installed
E: Unmet dependencies. Try using -f.

I'm certain I can find and fix this error. I'm more interested in knowing why the entirety of apt is broken because of one program having a problem.

Edit: I can't apt-get dist-upgrade either:

$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 guvcview : Depends: libguvcview-2.0-0 but it is not installed
            Recommends: uvcdynctrl but it is not installed
E: Unmet dependencies. Try using -f.

apt-get -f install is met with this error:

Preparing to unpack .../libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb ...
Unpacking libguvcview-2.0-0:amd64 (2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1) ...
dpkg: error processing archive /var/cache/apt/archives/libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb (--unpack):
 trying to overwrite '/usr/lib/x86_64-linux-gnu/libgviewaudio-2.0.so.2.0.0', which is also in package libguvcview-2.0-2:amd64 2.0.4+debian-1
dpkg-deb: error: subprocess paste was killed by signal (Broken pipe)
Errors were encountered while processing:
 /var/cache/apt/archives/libguvcview-2.0-0_2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

It should be noted that the file /usr/lib/x86_64-linux-gnu/libgviewaudio-2.0.so.2.0.0 does not exist on my system.

I can't do anything with APT because of this. I can't even remove an unrelated program. abiword is a text editor.

$ sudo apt-get remove abiword
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies:
 guvcview : Depends: libguvcview-2.0-0 but it is not going to be installed
            Recommends: uvcdynctrl but it is not going to be installed
 lubuntu-desktop : Depends: abiword but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

OS: Lubuntu desktop (Ubuntu 16.10)

Solution 1:

I found the answer here:

apt-get commands are failing with libpython3.3 unmet dependencies

Apparently I had two conflicting versions of guvcview installed.

apt list --installed | grep guvc
guvcview/yakkety,now 2.0.5+ubuntu2~ppa1+1418-0ubuntu1~201702081552~ubuntu16.10.1 amd64 [installed]
libguvcview-2.0-2/yakkety,now 2.0.4+debian-1 amd64 [installed]

As per the answer above, I used dkpg -r --force-depends to remove them:

sudo dpkg -r --force-depends guvcview
sudo dpkg -r --force-depends libguvcview-2.0-2

At that point I tried to apt-get upgrade again as normal:

sudo apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these.
The following packages have unmet dependencies:
 lubuntu-desktop : Depends: guvcview but it is not installed
E: Unmet dependencies. Try using -f.

Aha! This time I got an expected error message. guvcview is a package that lubuntu-desktop depends on: that means if I reinstall it after it's removed, everything should be back to normal, right?

After running these commands:

sudo apt-get -f install
sudo apt-get upgrade

Everything works now. guvcview is working again too, which is nice, because I broke it while debugging this error.