Firefox 25.0.1 ( issue started about a week ago with previous version had been working fine.
Win 7
Adblock Plus 2.4
Recently when opening youtube videos, the video starts for a sec or 2 them reloads. You see the play arrow but it will not activate with a click on the arrows, nothing happens.
I did find that when I add http in front of the address it will now play without the ad.
Perhaps youtube has changed something.
You Tube Won't play with ads blocked
Re: You Tube Won't play with ads blocked
Apparently, I cannot understand, what you exactly did to trigger this behaviour. If this is still up to date, please file a detailed step-by-step issue at https://issues.adblockplus.org