1374985 - Flash plugin not detected (but is installed)

Status: RESOLVED INVALID

(Core Graveyard :: Plug-ins, defect)

Description

[Smylers]

The Flash plugin is not being detected by websites, even though I have it installed.

For instance:
• What's My Browser reports ‘Flash version: Not installed’. There's no Lego brick in the URL bar to indicate that the page is trying to use Flash. My browser's detected details:
http://www.whatsmybrowser.org/b/CU8N2TV
• The Mozilla plugin checker reports ‘No plugins were found.’ https://www.mozilla.org/en-GB/plugincheck/
• Trying to watch a video on ITV redirects me to the Adobe Flash installer page: http://www.itv.com/

But:
• Adobe's flash checker page reports ‘You have version 26,0,0,131 installed’ (while confirming that is the latest version for Linux): http://get.adobe.com/flashplayer/about/
• about:plugins shows that Shockwave Flash is installed and handling .swf and .spl files
• about:addons shows I have Shockwave Flash 26.0.0.131, set ‘Always Activate’

I tried a clean profile without any extensions, and the problem doesn't exist there: visiting What's My Browser displays the Lego icon by the URL, and detects that I have flash. Details: http://www.whatsmybrowser.org/b/8QHRN41

So I tried disabling all extensions in my main profile, but the problem persists. There's clearly other setting in my profile that's triggering this bug.

browser.tabs.remote.autostart and browser.tabs.remote.autostart.2 are both false in my main profile. In the clean profile .autostart.2 was true, but I toggled it to false and still didn't see the bug there, so it doesn't seem to be e10s related.

Please let me know if there are any more config settings I can try tweaking to isolte this bug.

Build identifier: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:55.0) Gecko/20100101 Firefox/55.0

Comment 1

[Benjamin Smedberg]

Smyler, can I get you to attach the detailed support info from about:support? This sounds like a bug that existed for a few days in nightly but was fixed pretty quickly (bug 1370237). It might be interesting to see if the same workaround (removing pluginreg.dat) fixes the problem for you either temporarily or permanently.

Comment 2

[Smylers]

Attachment: about:support data from the profile with the bug

> Smyler, can I get you to attach the detailed support info from about:support?

Done.

> It might be interesting to see if the same workaround (removing pluginreg.dat) fixes the problem for you either temporarily or permanently.

No, it doesn't: I renamed pluginreg.data, restarted Firefox, and Flash still wasn't being detected. pluginreg.data got recreated, all bytes identical to the removed one.

Something which I should've been clearer about in my original report: Flash is running fine, on at least several sites — I'm guessing those which don't try to detect it but just attempt to use it unconditionally; the problem seems specific to detecting it in JavaScript.

Comment 3

[Benjamin Smedberg]

You are running with the privacy.resistFingerprinting pref set to true. The behavior you have described is the expected behavior with that pref: plugin information is not available with navigator.plugins or navigator.mimeTypes, and so sites that use those will not see the Flash plugin.