Hi, 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.

In future if not doing so please download from here :

• https://www.mozilla.org/firefox/all/

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

Hello, Thanks for your quick answer.

I had already read all these supports when looking for help by myself ;-)

So, When I shut down Firefox and open it again....all is ok When I shut down my computer, open it again and open Firefox again...all is ok And I'm usually very happy using this program.

BUT, when Firefox make an update, he don't want to open again because he don't find my profil And this arrives after every udate since a few months!!

So I think it is a bug with update program

I know that it is nogood to do that but I just disactivated the detection of update :-(

Try to open the Profile Manager to create a new profile.

See "Creating a profile":

• https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer files from a previously used profile to the new profile, but be cautious not to copy corrupted files to avoid carrying over problems.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

See also:

• https://appletoolbox.com/2016/07/fix-corrupt-user-accounts-macos/

Damned... I think that it is robots who answer me .... Hope not ;-) Or maybe he don't read all my request!!

So... I don't understand:

Why create a new profile since my Firefox functions well??

This bug of profil lost arrive when Firefox trie to start again after an update So, how could I following all your solutions since Firefox refuses to open?

If Firefox can't find the profile then you either need to recover your previous profile or you need to create a new profile.

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

You can check if you have an orphaned profile that isn't registered in profiles.ini and that doesn't show in the Firefox Profile Manager.

You can recover an orphaned profile via these steps:

• use the Profile Manager to create a new profile
  https://support.mozilla.org/en-US/kb/profile-manager-create-and-remove-firefox-profiles
• click "Choose Folder" in the Profile Manager
• browse to the location of this profile to register this profile in the Profile Manager and use this profile

See "Profile was moved or renamed":

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

Note that you should never use "Choose Folder" to specify a folder that already contains files that do not belong to Firefox. Only use "Choose Folder" to recover an profile that isn't listed in the Profile Manager.