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Dustin, Mac Support Specialist
Category: Mac
Satisfied Customers: 13095
Experience:  Over a decade putting the missing byte back into Apple. Also worked in The US Army as A Network Switching Systems Operator/Controller
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When I click on this streaming video from Firefox 47.0: I

Customer Question

When I click on this streaming video from Firefox 47.0:
I get an error message "Video cannot be played because the file is corrupt."
However ther same video plays if I click on it from Safari 9.0.1. In both cases, I'm running ElCapitan 10.11.1
Isn't the error message misleading? If the file plays correctly in Safari, how can the source fiule be corrupt?
How do I fix the problem with Firefox?
Submitted: 11 months ago.
Category: Mac
Expert:  Dustin replied 11 months ago.

Welcome to, my name is ***** ***** I will do my best to assist you.

If you are the webmaster for that website, I suggest converting the movie to a different format, such as .avi and then reposting the video. Other wise, firefox cant install the quicktime plugin and cant play .mov files.

with that being said, if you are not t he webmaster, there is a change you can make to firefox internaly which may allow the video to play

In a new tab, type or paste about:config in the address bar and press Enter/Return. Click the button promising to be careful.

(2) In the search box above the list, type or paste mp4 and pause while the list is filtered

(3) Double-click the media.mp4.enabled preference to switch it from true to false

I strive to provide great service, and greatly appreciate a 5 star rating clicked and submitted when you are satisfied.. I always answer follow up questions.

Dustin S.

Senior Technician and Network Switching Systems Operator / Maintainer.

Customer: replied 11 months ago.
Justin - As a software support professional, it is your responsibility to report bugs to the relevant product development team.
You did figure out that the Quicktime .mov movie format is now considered a legacy format, and .mp4 and .html5 are current formats. You did not respond to the fact that the error message I reported from Firefox (using the Flash player) was misleading. That is a bug fix that you should have reported to Adobe and/or Mozilla.There is a perception, and I think it's a valid one, that a pay-for-customer-support service such as JustAnswer actually opposes cleaning up bugs in the ecosystem, because it's easy money to just keep them around for people to trip over.
I worked in the software industry for 25 years, and the ethic was always to work cooperatively to stomp out bugs, and it didn't matter who you were working for. Keeping a clean ecosystem is a shared responsibility.If you went ahead and reported the misleading error message bug, please disregard my comment. However, when you take that proactive approach, you will get a higher rating by reporting to the customer that you took that additional step.I would have given you a 5 if you reported the bug. If you take that step, I'll give you a high 5.
Expert:  Dustin replied 11 months ago.

I understand what you are saying, and agree with it. However in this situation there are already several pages dedicated as known bug reports for the same specific issue we were discussing.

In fact it was from that bug report page that I pulled the suggested workaround here """ Double-click the media.mp4.enabled preference to switch it from true to false""

Normally, before I file any bug / error / condition reports I check to see whether similar reports are already in place. Dual submitting bugs is frowned upon in the firefox forums.

I hope that answers your question / concern about the bug?

With that being said, were you able to make the change in the about:config section and get the .mov files working in FF ?

Dustin S.

Senior Technician and Network Switching Systems Operator / Maintainer.

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