Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

Problem persists even after firewall is turned off and machine is restarted.

Problem persists in safe mode, too.

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select Network.

[56+] Type about:preferences#general<enter> in the address bar. Look for Network. +++++++++++++++++++++ Look for Configure How Firefox Connects and press the Settings button. If you are using a proxy, make sure those settings are correct. If there is no proxy, first try No Proxy. If there is a problem, then try System Proxy.

Thanks for the suggestion, but, because of the spinning wheel, the application is completely unusable, and it is not possible to type anything in the address bar.

Hi, please grab a copy of your Profile :

• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data ( I hope this includes Mac )

REFRESH INSTRUCTIONS Please try a Refresh but Note that this does more than uninstalling and re-installing does. Normal uninstalling does not remove some preferences which may have become corrupt. Please Refresh but do this 1st: Delete your Cookies and Cache and TEST.

• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer
• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

then

• https://support.mozilla.org/en-US/kb/refresh-firefox-reset-add-ons-and-settings

TEST....... If no issues then Extensions which need to be added back in 1 at a time and tested ..... Or it is your Profile : Make a new one and test ...:

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

If is your Profile :

• https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile
• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Note: Any customization will revert back to default, you will also need to reinstall Extensions.

Please let us know if this solved your issue or if need further assistance.

••••••Bumping up to PKShadow's attention, thanks!•••••

Hi, thanks, I look forward to trying this.

A couple of questions first:

1. Do all of the steps about "Grabbing my profile" and backing it up only matter if I care about what's stored on the machine in question? IOW, if I have a working Firefeox install on another machine, and am happy with all aspects of that, can I just essentially wipe everything on the machine where Firefox isn't working, then install, then just sign in and get my profile back that way?

1. Also when you say delete cookies and empty cache, are you talking about doing this in other browsers? Because, again, I can't access any functionality of the Firefox app on the machine in question, due to the spinning wheel.

Thanks!

What Firefox version were you using before? Do you want to go back?

You could also check out ESR

Firefox; Extended Support Release {web link} ESR Notes System Requirements

@FredMCD,

Not sure, but it was probably from a few years ago. I had abandoned it for quite some for Chrome but rethought that decision recently as so many no doubt are.

ESR might be over my head.

sutto said

Do all of the steps about "Grabbing my profile" and backing it up only matter if I care about what's stored on the machine in question?

If there is nothing in the old profile that you want, you don't need to back it up. If you want, you can do is delete the old and Firefox will create a new one.

if I have a working Firefeox install on another machine . . . .

You could, if you want, Copy that profile to the new profile(above). Another way would be to use sync. Note: Different browser versions may not support some setting and/or add-ons.

Also when you say delete cookies and empty cache, are you talking about doing this in other browsers?

What would be for website issues. not when the browser won't start.

sutto said

. . . but it was probably from a few years ago. I had abandoned it for quite some for Chrome

It's possible the old profile is not useful by the new version. Things get changed abound, some options removed, others added . . . . . .

You would be better off removing the old profiles and creating a new one using the current version.

http://kb.mozillazine.org/Profile_folder_-_Firefox#Navigating_to_the_profile_folder

https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles

https://support.mozilla.org/en-US/kb/how-run-firefox-when-profile-missing-inaccessible

https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles

Thanks, @FredMcD! (and @PKShadow, who gave similar advice).

I followed the directions here to remove a profile (by using Terminal to open the Firefox profile manager without opening Firefox): https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles#w_removing-a-profile

I closed Terminal.

I launched Firefox, and everything worked just like it was supposed to. I was able to sign in and sync perfectly with my Firefox account.

All solved, thanks again! Really glad to get Chrome out of there....

Glad to help. Safe Surfing.