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Why makes Firefox 40 unresponsive?

  • 8 replies
  • 3 have this problem
  • Last reply by John99

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Beginning with Firefox 40, if I:

- go to
- search for a domain (e.g. "")

Firefox becomes almost completely unresponsive.

E10s is enabled, but I get the same results in a "New non-e10s" window, or by starting with a new clean profile.

I have tried with Firefox 39 and it works fine. Can anyone else confirm the problem?


All Replies (8)

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Since this is an issue in Nightly it is possible that there was an update since you posted this thread.

Since updates are happening each day, Nightly issues are best noted in For nightly the template link is here:

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Thanks for your response, guigs2.

I have first posted it here because on suggests to first ask on the support forum before creating a new bug.

The problem is with firefox-40, the current developer edition. It is automatically updated at least two times per day, and it is restarted when prompted. After each restart, I try to use to see if it works, but I still see the problem.

Since it takes just a few seconds to test it, can you confirm that the problem exists? If yes, I will feel more confident to create a new bug.

Thanks for your help.

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I can confirm it works on a Mac

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I see the same on Linux the current DE and Nightly build. I only see spinning rotators of the result page and I have to force a quit.

You can try to post in the daily thread at the mozillaZine Builds forum.

You need to register at the mozillaZine forum site to be able to post in that forum.

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Thanks guigs2 and cor-el for your feedbacks. I think the problem is with memory usage. Starting with Firefox-40, memory usage on is much higher, thus trashing firefox's performance on lower end machines. Macs are tipically more powerful, maybe that is why it works for guigis2.

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This works ok for me on a severly memory challenged Firefox Release fx38.0.5 (Not yet tested other Fx versions. I now have a rebuilt machine avaiable so will do so soon have multiple installs of Firefox available for testing)

If you do file a bug let us know the bug number. You may also wish to try using the tool mozregression, that lets you pin down exactly where the problem occurred.

Also note you will be able to study firefox's memory usage by keying in about:memory does usge of the site on Fx40 cause big increases in memory usage ? (If so keyword memshrink may be appropiate on the bug)

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@John99, it works perfectly on anything older than firefox-40. The problem is only with firefox-40 and beyond. When I need to go to, I start a new instance of firefox-39 and it works smoothly.

As suggested by cor-el, I have asked for help on . But I am waiting for the moderator to approve the message.

I have not submitted a bug report because I dont know how to use bugzilla well, and did not want to fill it with low quality reports... I will try to find time to do it...

For now, thanks for your helpful tips. I will check about:memory, and will report the results.

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The people over at mozillazine may already be awareof the issue and know what causes it. If not then mozregression is pretty handy if you wish to file a good quality bug.

If you do decide filing a bug is appropriate have a look at