Google Chrome can't play YouTube video since few days before.

  • Google Chrome version: 12.0.742.100
  • Flash player version:
  • Mac OSX version: 10.6.7
  • Extension installed: Tempermonkey , XML Tree


  • When YouTube video is played, audio only
  • video area is transparent, revealing the contents behind Chrome
  • when right click on the video area, the contents behind Chrome are clicked
  • When Firefox 5 views YouTube , Flash Player crashes
  • When Safari 5 views YouTube , it hangs (needs Force Quit)
  • Since it happens, VLC cannot play video anymore (sound only)
  • QuickTime works fine
  • Issue only happens in YouTube site
  • also happens in Incognito mode

I wonder if YouTube uses HTML5 player for Chrome or not.

  • YouTube only uses the HTML5 player if you opt-into it.
    – Wuffers
    Jun 27, 2011 at 4:02
  • @Mark: how to opt-in / out ?
    – Raptor
    Jun 27, 2011 at 10:11
  • 1
    Go here.
    – Wuffers
    Jun 27, 2011 at 14:11
  • after I joined the HTML5 Trial and view a video, the whole page become transparent !!!
    – Raptor
    Jun 28, 2011 at 0:47
  • Whoops?
    – Wuffers
    Jun 28, 2011 at 0:49

1 Answer 1


I have:

  • The same version of Chrome
  • The same version of Flash
  • Mac OSX 10.6.8

I do not see Tempermonkey available in Google Extensions, but I install XML Tree and was not able to repro the problem.

I do see something called Tampermonkey, and that could definitely be causing your problem. I would try uninstalling it and re-starting Chrome to check. If so, you have probably installed a script that has mucked up youtube. Go through your installed scripts and remove them until you find your problem.

Edit: It could be a quicktime problem if you are seeing a problem with HTML5 videos also.

  • i'll try to re-install QuickTime to see if the problem persists. Thanks.
    – Raptor
    Jul 5, 2011 at 3:32

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