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Why I can't use both "normal" firefox and firefox developers edition same time anymore?

  • 6 replies
  • 2 have this problem
  • Last reply by raggatah

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Hello, after new Firefox updates I can't use both Firefox editions at same time anymore. This is not good feature because I'm used to use both editions at same time when coding different softwares. Could you change this back, please?

Best regards, Pasi Nissinen

All Replies (6)

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I just tested and there are no issues with running Firefox and Firefox Developer Edition at the same time.

You should check that you have the option to do so enabled in your settings. Go to the General tab of the Firefox Developer Edition settings page and ensure that the Allow Firefox Developer Edition and Firefox to run at the same time option is enabled.

Firefox Developer Edition runs on a separate profile from Firefox, so there should be no issues running the two side-by-side or testing things in Firefox Developer Edition without impacting your regular Firefox installation.

NOTE: You will be prompted to restart Firefox if you change this setting.
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Hello Wesley, Thank you for you answer. That's how it worked for me as well for few days ago. But after new update on Firefox developer I get message (linked picture 1) and I have to close another Firefox first.

Second picture indicates that I have enabled option "run at the same time".

So something funny is happened here.

Best regards, Pasi Nissinen

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If you are accessing Firefox Developer Edition from a shortcut from your Windows desktop, try changing the target of that shortcut to:


See if that allows you to open both Firefox Developer Edition and Firefox at the same time.

If not, try reinstalling Firefox Developer Edition to ensure that nothing in the installation is damaged from the update.

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Hello Wesley, thank you for you answer and help. But it didn't help solve the problem. I tried to reinstall both Firefox and Firefox Developer Edition and change the shortcut, but no change.

I guess I have to live with it. :)

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Does it has effect if you add the "-no-remote" switch to the command line of either shortcut?

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I have the same problem on macOS Mojave 10.14.1 and my option is enabled.This is happening for some time now.Also when I close the one and open the another it restores the same session and this was not how it used to be.