Separate Security Issue: Update your Flash Player Note: Windows users should download the active_x for Internet Explorer. and the plugin for Plugin-based browsers (like Firefox).

Note: Windows 8 and Windows 10 have built-in flash players and Adobe will cause a conflict. Install the plugin only. Not the active_x.

Flash Player Version: 24.0.0.194

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download. <Windows Only>

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download. <Windows Only>

See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

You are talking of the about:newtab page, Yes? Have you cleared your history? Removed anything thru Firefox or another program?

FredMcD said

You are talking of the about:newtab page, Yes? Have you cleared your history? Removed anything thru Firefox or another program?

I'm not in any way "technical", so I don't understand your first question. I'm talking about when you visit a website and want to keep it, but not in the Bookmarks Toolbar--so you "pin" it. These are sites I use all the time.

No, I haven't cleared my history.

Since I wrote the support request I had gone back and pinned a couple of the sites I always have there. Then I followed your instruction to download the latest version of Flash Player--during which I specified that I have Windows 7 and Firefox; and when I reopened Firefox, the new pins had been cleared...

Make sure that you do not run Firefox in permanent Private Browsing mode.

This can also be caused by a problem with the sessionstore.js file.

This file stores currently open tabs and also all pinned tabs.

I apologise for my ignorance cor-el, but I have no idea what anything in your reply means.

I've just put the words "permanent private browsing mode" into the search bar in Help--because I've never heard of it before, so don't know how to see if it's switched on or off--and there's no useful advice.

As for sessionstore.js... Nope, no idea at all what that is and I can't find anything on the sessionstore.js Help page that refers to disappearing pinned tabs.

See:

• https://support.mozilla.org/kb/Private+Browsing

• Options/Preferences -> Privacy -> Firefox will: "Use custom settings for history"
  Deselect: [ ] "Always use Private Browsing mode"

Currently set to "Remember History".

Firefox uses sessionstore.js in the profile folder to store session data. Sessionstore.js is only present when Firefox is closed. The sessionstore.js file is created from recovery.js when you close Firefox and is removed and copied to previous.js when you start Firefox to make is possible to restore the session at any time.

Backup the session files in the sessionstore-backups folder in the Firefox Profile Folder to make sure not to lose possible important session data. Do NOT close Firefox when Firefox is already running.

You will normally find these files in the sessionstore-backups folder:

previous.js (cleanBackup: copy of sessionstore.js from previous session that was loaded successfully)
recovery.js (latest version of the sessionstore written during runtime)
recovery.bak (previous version of the sessionstore written during runtime)
upgrade.js-<build_id> (backup created during an upgrade of Firefox)

You can copy a file from the sessionstore-backups folder to the main profile and rename the file to sessionstore.js to replace the current file (make a backup copy of the current sessionstore.js).

See also:

• http://www.ghacks.net/2014/06/27/mozilla-launches-improved-session-restore-firefox-33/

sessionstore.js is noe of the files in the profile folder.

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