When you enable HDXMediaStreamingForFlash for iexplore process then you start encounter various issues in loading Flash based web sites in particular Youtube.com. It may turn out to “Youtube.com is not responding…”, and when you see the debug information with "errorCode":203,"messageKey":"HTML5_DEFAULT_FALLBACK"
{"ns":"yt","el":"detailpage","hl":"en_US","cr":"GB","cpn":"TKkzTuloUM0_uv0X","docid":"PodEqBpTK8Q","ver":2,"referrer":"http://www.youtube.com/my_videos?o=U","cmt":"0","plid":"AATvw2oxEmyRpdSh","ei":"Nm7SUoqdBLOTigblsIHAAw","fmt":"134","fs":"0","rt":"14.209","c":"WEB","cver":"html5","adformat":null,"content_v":null,"euri":null,"subscribed":null,"lact":10421,"live":null,"cplatform":null,"cbrand":null,"cmodel":null,"cnetwork":null,"cbr":"Chrome","cbrver":"31.0.1650.63","cos":"X11","cosver":null,"mos":0,"q":null,"osid":null,"state":null,"volume":100,"uga":"m17","len":"152","fexp":"921906,913564,926515,916626,929305,930901,902545,942901,938630,936910,936913,907231,907240,921090","vct":"0.000","vd":"NaN","vpl":"","vbu":"0.000-10.101,","vpa":true,"vsk":false,"vpr":1,"vrs":0,"vns":3,"vec":null,"lct":"0.000","lsk":false,"lmf":false,"lbw":"130000.000","lhd":"0.383","ltd":"4758.952","laa":"i=140,r=159748-163328,t=10.0,10.2","lva":"i=134,r=755853-784592,t=10.0,10.4","lar":"i=140,r=816-815,t=0.0,0.0","lvr":"i=134,r=1113-1112,t=0.0,0.0","debug_error":{"errorCode":203,"messageKey":"HTML5_DEFAULT_FALLBACK","message":"This video is currently unavailable."},"debug_videoId":"PodEqBpTK8Q","debug_playbackQuality":"medium","debug_date":"Sun Jan 12 2014 10:28:21 GMT+0000 (GMT)"}
Fix is to disable the HDX Flash streaming for iexplore process by deleting below key:
HKEY_LOCAL_MACHINESOFTWAREWow6432NodeCitrixCtxHookAppInit_DllsHDXMediaStreamForFlashiexplore.exe
