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Firefox will not open

  • 3 replies
  • 4 have this problem
  • 6 views
  • Last reply by idazel

idazel
idazel
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When I click to open Firefox, it comes up for a second and then goes away. If I go over the icon on the task bar it shows Firefox opened, but it does not open. Firefox says if this happens the settings are corrupt and I should create a new profile under the profile manager. But if you cannot get Firefox to open you cannot open the profile manager and you cannot create a new profile. From what Firefox is saying, that I cannot re-install Firefox, I can never use Firefox on this computer again. Is that correct?????

When I click to open Firefox, it comes up for a second and then goes away. If I go over the icon on the task bar it shows Firefox opened, but it does not open. Firefox says if this happens the settings are corrupt and I should create a new profile under the profile manager. But if you cannot get Firefox to open you cannot open the profile manager and you cannot create a new profile. From what Firefox is saying, that I cannot re-install Firefox, I can never use Firefox on this computer again. Is that correct?????

Chosen solution

No, that isn't correct at all. You just have to manually create a Fresh profile.


  1. Press the following shortcut to get a Run window: [Windows] + [R]. This should bring up a window that contains a text field.
  2. In that text field, enter %APPDATA% and press Enter. An explorer window should open.
  3. From that explorer window, right click on the "Mozilla Folder" click "Rename", and rename the folder to "Mozilla.Old". Hang onto this folder, it will be important later.
  4. Reopen Firefox. It should create a new Mozilla Folder with a new profile in it.
  5. Now read Recovering important data from an old profile and transfer your data from your old profile (the mozilla.old folder) to your new one.
Read this answer in context 👍 1

All Replies (3)

user633449
user633449
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Chosen Solution

No, that isn't correct at all. You just have to manually create a Fresh profile.


  1. Press the following shortcut to get a Run window: [Windows] + [R]. This should bring up a window that contains a text field.
  2. In that text field, enter %APPDATA% and press Enter. An explorer window should open.
  3. From that explorer window, right click on the "Mozilla Folder" click "Rename", and rename the folder to "Mozilla.Old". Hang onto this folder, it will be important later.
  4. Reopen Firefox. It should create a new Mozilla Folder with a new profile in it.
  5. Now read Recovering important data from an old profile and transfer your data from your old profile (the mozilla.old folder) to your new one.
dumdidadida
dumdidadida
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See also: New profile

Profiles Howto

Profile Manager

Firefox Profile Folder

If you have security software (antivirus, firewall etc.) installed, you can try deleting all existing instances of Firefox and its related files in all the different configuration areas/modules of the security software. Instead create new allow/trusted rules for Firefox + its related processes. Even otherwise the security software may also ask again when Firefox is started and you can try to allow/trust at that time. Please see this.

AV/Firewalls Configuration

Modified by dumdidadida

idazel
idazel Question owner
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Thank you very much. I did this and restored my old files in the new profile and it appears to be working correctly now. Have a great day.