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Can't install add-ons

  • 13 replies
  • 11 have this problem
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  • Last reply by cor-el

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I cannot install add-ons. When I click "Install Now" I get a message that reads "Stumbleupon could not be installed becuase Firefox cannot modify the needed file."

I can't install any add-ons.

I cannot install add-ons. When I click "Install Now" I get a message that reads "Stumbleupon could not be installed becuase Firefox cannot modify the needed file." I can't install any add-ons.

Chosen solution

Firefox 12 doesn't have the reset button.

You will have to update to Firefox 13 if you want to use that reset button instead of the terminal method to create a new profile.

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It is possible that there is a problem with the file(s) that store the extensions registry.

Delete the files extensions.* (e.g. extensions.sqlite, extensions.ini, extensions.cache) and compatibility.ini in the Firefox profile folder to reset the extensions registry.

New files will be created when required.

See "Corrupt extension files":

If you see disabled, not compatible, extensions in "Tools > Add-ons > Extensions" then click the Tools button at the left side of the Search Bar (or click the "Find Updates" button in older Firefox versions) to check if there is a compatibility update available.

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I can't find the profile folder anywhere. I see the Mozilla folder, but nothing with profiles

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You can use this button to go to the Firefox profile folder:

  • Help > Troubleshooting Information > Profile Directory: Open Containing Folder
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OK, thank you. I got into the folder the way you said and deleted all of the files except I could not find extensions.cache. I looked in all the folders too. I tried the addon again and same result.

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Create a new profile as a test to check if your current profile is causing the problems.

See "Basic Troubleshooting: Make a new profile":

There may be extensions and plugins installed by default in a new profile, so check that in "Tools > Add-ons > Extensions & Plugins" in case there are still problems.

If the new profile works then you can transfer some files from the old profile to that new profile, but be careful not to copy corrupted files.

See:

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"Use the instructions in the Managing profiles article to start the Profile Manager and create a new profile."

I go to https://support.mozilla.org/en-US/kb/troubleshoot-and-diagnose-firefox-problems?redirectlocale=en-US&redirectslug=Basic+Troubleshooting#w_8-make-a-new-profile

Directions: "On the menu bar, click on the Firefox menu and select Quit Firefox. Navigate to /Applications/Utilities. Open the Terminal application. In the Terminal application, enter the following: /Applications/Firefox.app/Contents/MacOS/firefox-bin -p"

Terminal says: "No such file or directory"

Obviously the firefox bin is there, I looked, but opening in in it's folder just launches the Firefox browser.

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Is it possible I do not have a profile at all? Could that be the problem?

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In Firefox 13+ you can also use reset Firefox via "Help > Troubleshooting Information" to create a new profile:

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I don't have a reset button. There is no box on the right. The text goes the whole width of the page without a reset button.

And for the 20th time I've deleted Firefox and every single file of Firefox that I could find and reinstalled with the same issue, and no reset button

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And it is Firefox 12 I am using

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Chosen Solution

Firefox 12 doesn't have the reset button.

You will have to update to Firefox 13 if you want to use that reset button instead of the terminal method to create a new profile.

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Sorry, I miss read. It's working now. Thank you very much for your time and patience with me!

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You're welcome