For some odd reason, every single time I try and view a flash post it says "Missing Plug-in". This came out of the blue, one day it was working the other it was not. I un-installed my browser (Deleting all cookies, plug-ins, etc.) and re-installed. I downloaded all the same plug-ins I had before one at a time, testing to see if any of them in particular had anything to do with the issue, and I got nothin'. So, I have absolutely no idea why, but for some reason I can not view ANY flash posts.

TL;DR, Can't view Flash Posts, wut do?

Are you using Chrome?

Yes I am.

See: http://e621.net/forum/show/27579

I just tried that to download that Extension, but it does not seem to have resolved the issue... Maybe I'm retarded?

Hmn. Chröm has been having issues lately. It's not just you. Unfortunately, I'm no programmer, or anything of the sort.

Oh well then~
If any one comes up with a solution (That works with Google Chrome) please post it here.

Apparently going straight to the file's location on the server (via the Download link) works.

Download the most recent version of chrome. It works now.

I only had an issue in Chrome in Windows 7, but I'm in Windows so rarely that I didn't care enough to do anything about it.

But Aurali says it's fixed.