Create a new profile to test if your current profile is causing the problem.

See "Creating a profile":

• https://support.mozilla.org/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

You can copy files like these to the current Firefox profile folder to recover specific data.

• bookmarks and history: places.sqlite
• bookmark backups: JSON backups in the bookmarkbackups folder
• SQLite files like cookies.sqlite (cookies) and formhistory.sqlite (saved form data)
• logins.json and key3.db (decryption key) for Passwords saved in the Password Manager
• cert8.db and possibly cert_override.txt for (intermediate) certificates stored in the Certificate Manager
• persdict.dat for words you added to the spelling checker dictionary
• permissions.sqlite for Permissions and possibly content-prefs.sqlite for other Site Preferences
• sessionstore.js for open tabs and pinned tabs and tab groups

Help! I have created a new profile 3 Xs, but Firefox reverts to the default every time I reboot! Then when look for the Profile with terminal it olnly shows Default. The last time I created a profile I selected it & checked the box for "Load Selected acount" There doesn't seem to be a file for FireFox in the Library/Application Support/Firefox/profiles even though that's where it says it will save my profile

There is software like Advanced SystemCare with its Surfing Protection feature that can protect files in the Firefox profile folder against changes. If you have such software then check the settings or uninstall this software.

Thanks for the input. I don't remember installing this or any equivalent. How would I check for such a thing?

Boot the computer in Windows Safe Mode with network support (press F8 on the boot screen or hold down the Shift key) to see if that has effect.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/
• http://www.7tutorials.com/4-ways-boot-safe-mode-windows-10

I'm running OSX on a Mac...

Sorry, somehow I thought I was posting to the OSX group. Maybe you could redirect me?

Oops sorry, I forgot to check the system details to see your OS, but is could still be possible that your Mac could have security software installed that behave similarly.

There is no special section for each OS on this forum, so you are fine here. I normally click the link to go to the last post and then I miss the system details. Such specific issues are more likely on Windows than on other platforms like Mac and Linux. If it only happens on a reboot then it must be caused by software that runs once during boot time.

OK. It's funny because going through Terminal worked to allow me to set up a profile and even though the profile is gone after re-boot I can start Terminal again, click create new profile and when asked where to save the file I clicked "choose" and it takes me to the folder it saved the last one. There are now 5 "susan" profiles! Choosing any one loads the profile, can be selected, & Firefox then boots with my settings! Not a real help, but interesting. I guess I'll go back to Chrome 'til I figure out what software might be causing the problem!

BTW If you can make anything of it here is the Terminal transcript of the process I just said above:

/Applications/Firefox.app/Contents/MacOS/firefox-bin -P

Last login: Sun May 15 20:52:22 on ttys000 Susans-MBP-3:~ susanmkennedy$ /Applications/Firefox.app/Contents/MacOS/firefox-bin -P Susans-MBP-3:~ susanmkennedy$ 1463366942735 addons.xpi-utils WARN Disabling foreign installed add-on 837a165494f7440b8dc6b1ff2bf06@79bf096c24fc443d8b018a.com in app-system-user 1463367230814 FirefoxAccounts ERROR Error updating FxA account info: Error: A different user signed in (resource://gre/modules/FxAccounts.jsm:162:29) JS Stack trace: AccountState.prototype.resolve@FxAccounts.jsm:162:29 < getUserAccountData/<@FxAccounts.jsm:146:14 < Handler.prototype.process@Promise-backend.js:933:23 < this.PromiseWalker.walkerLoop@Promise-backend.js:812:7 < this.PromiseWalker.scheduleWalkerLoop/<@Promise-backend.js:746:11 1463367230814 FirefoxAccounts ERROR Error updating FxA account info: Error: A different user signed in (resource://gre/modules/FxAccounts.jsm:162:29) JS Stack trace: AccountState.prototype.resolve@FxAccounts.jsm:162:29 < getUserAccountData/<@FxAccounts.jsm:146:14 < Handler.prototype.process@Promise-backend.js:933:23 < this.PromiseWalker.walkerLoop@Promise-backend.js:812:7 < this.PromiseWalker.scheduleWalkerLoop/<@Promise-backend.js:746:11 1463367230814 browserwindow.syncui ERROR updateUI failed: Error: A different user signed in (resource://gre/modules/FxAccounts.jsm:162:29) JS Stack trace: AccountState.prototype.resolve@FxAccounts.jsm:162:29 < getUserAccountData/<@FxAccounts.jsm:146:14 < Handler.prototype.process@Promise-backend.js:933:23 < this.PromiseWalker.walkerLoop@Promise-backend.js:812:7 < this.PromiseWalker.scheduleWalkerLoop/<@Promise-backend.js:746:11 1463367230814 browserwindow.syncui ERROR updateUI failed: Error: A different user signed in (resource://gre/modules/FxAccounts.jsm:162:29) JS Stack trace: AccountState.prototype.resolve@FxAccounts.jsm:162:29 < getUserAccountData/<@FxAccounts.jsm:146:14 < Handler.prototype.process@Promise-backend.js:933:23 < this.PromiseWalker.walkerLoop@Promise-backend.js:812:7 < this.PromiseWalker.scheduleWalkerLoop/<@Promise-backend.js:746:11 WARNING: content window passed to PrivateBrowsingUtils.isWindowPrivate. Use isContentWindowPrivate instead (but only for frame scripts). pbu_isWindowPrivate@resource://gre/modules/PrivateBrowsingUtils.jsm:25:14 getTopWin@chrome://browser/content/utilityOverlay.js:53:19 openLinkIn@chrome://browser/content/utilityOverlay.js:236:11 openUILinkIn@chrome://browser/content/utilityOverlay.js:196:3 openHelpLink@chrome://browser/content/utilityOverlay.js:727:3 helpButtonCommand@chrome://browser/content/preferences/in-content/preferences.js:164:3 1463367544005 addons.update-checker WARN Update manifest for e10srollout@mozilla.org did not contain an updates property 1463367544143 addons.update-checker WARN Update manifest for firefox@getpocket.com did not contain an updates property 1463367544436 addons.update-checker WARN Update manifest for {972ce4c6-7e08-4474-a285-3208198ce6fd} did not contain an updates property 1463367545002 addons.xpi ERROR Failed to clean updated system add-ons directories.: Unix error 2 during operation DirectoryIterator.prototype.next on file /Users/susanmkennedy/Library/Application Support/Firefox/Profiles/features (No such file or directory) ((unknown module)) No traceback available 1463367545559 addons.xpi ERROR Attempted to load bootstrap scope from missing directory /Users/susanmkennedy/Library/Application Support/Firefox/Profiles/extensions/firefox-hotfix@mozilla.org.xpi 1463367545560 addons.xpi WARN Add-on firefox-hotfix@mozilla.org is missing bootstrap method startup 1463367668078 addons.xpi WARN Add-on firefox-hotfix@mozilla.org is missing bootstrap method shutdown

Any help out there? I've tried everything suggested here, but nothing has solved my problem!!! I really want to make Firefox my default browser, but this is annoying enough to prevent me from doing this!

Do you have any security software running on your Mac computer?

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

• Help -> Troubleshooting Information -> Profile Directory:
  Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder
• http://kb.mozillazine.org/Profile_folder_-_Firefox

Try to rename (or delete) the ~/Library/Application Support/Firefox/ folder to see if the new profile structure works better.

• ~/Library/Application Support/Firefox/Profiles/<profile>/