I recently ran into an issue I'd like to talk about in case anyone else has hit the same problem.
On my main PC, I run Manjaro Linux (an offshoot of Arch Linux). Recently, when I tried to to perform a system update, I started getting errors preventing me from updating. The problem was a conflict relating to package "ffmpeg2.8", which was in turn required by "4kvideodownloader". Now, you may or may not be familiar with 4kvideodownloader, but the details of it aren't especially important (aside from the fact that it's freaking awesome and I highly recommend it). What is important here is that I like 4kvideodownloader, and there are reasons I don't want to give it up.
This left me with a dilemma. The 4kvideodownloader tool (via its "ffmpeg2.8" dependency) were blocking me from updating my machine. The obvious choices were to either stop making any updates to my machine forever, or uninstall both "ffmpeg2.8" and "4kvideodownloader". I hated both options.
So I took a gamble. I uninstalled both "ffmpeg2.8" and "4kvideodownloader", hoping I would then be able to update my Manjaro/Arch-ish system and then...somehow...be able to get "4kvideodownloader" installed and working again.
Which brings me to the whole point of this post:
The gamble paid off! Once I uninstalled "ffmpeg2.8" and "4kvideodownloader" via yaourt (turns out, both are AUR packages), I had no trouble updating my system. And then, best of all, I had no trouble re-installing "4kvideodownloader" (along with its dependency, "ffmpeg2.8") afterwards.
Summary (ie, that's ordinary English for "TL;DR", for any of you hipster, fashion, Portlandia-as-everyday-life nerds out there.) :
You don't have to give up 4kvideodownloader, or wait for a AUR update to 4kvideodownloader, to update your Arch Linux-based system. Just uninstall them so you can update your system, and then you should have no trouble re-installing both. It worked for me...