It might be happens that the firefox doesn't close properly before restarting it.So Restarting Computer can restore them.

See this : http://mzl.la/MsnLrN

This thread is for older version firefox but works so,if you think that the above is not working then once you have to read this :

https://support.mozilla.org/en-US/questions/966704

What was the add-on and how did you remove it?

Did you notice any other unusual changes in Firefox?

To see whether you can restore any of Firefox's automatic bookmark backups, please see this article: Restore bookmarks from backup or move them to another computer.

Please Note: Using the Restore feature completely replaces your existing bookmarks, so it will wipe anything new you have added since the last backup. To preserve the ones you have now for potential restoration, export your current bookmarks before the restore, and then you can import them afterwards. These article has those procedures:

• Export Firefox bookmarks to an HTML file to back up or transfer bookmarks
• Import Bookmarks from an HTML file

Did you use Firefox's Reset feature? If so, there should be a new folder on your desktop named Old Firefox Data. Please do not delete that.

If you manually deleted files from your Firefox profile folder that might still be in the recycle bin, check in there for a file named places.sqlite and a folder named bookmarkbackups and get those to a safe place for potential future use.

If you used cleanup software to quarantine files from your Firefox profile folder, check the quarantine for a file named places.sqlite and a folder named bookmarkbackups and make sure those don't get flushed.

Let us know what you found.

What is the "Reset" feature? There is no "Old Firefox Data" folder on my desktop.

I did not delete any bookmarks manually, and there are no related items in the recycle bin.

I searched the C: driver for places.sqlite and bookmarkbackups folder; I cannot locate either (assuming I performed the Windows 7 search properly).

I did not quarantine any files other than the advertisement add-on which avast! removed.

Many of my other less-important settings have defaulted.

None of my data files have been affected.

Thanks, but I have tried those suggestions; they did not halp.

I am not an expert on avast! but if you are missing all of your history and settings, it may have lobotomized your Firefox profile. Does avast! have any record of what it deleted or did it quarantine anything that you might be able to restore?

Windows hides your Firefox profile folder from regular searches. This article describes how to get Windows to show hidden files and folders so that you can browse them or find them in a search: http://windows.microsoft.com/en-us/windows/show-hidden-files

Regarding Firefox's Reset feature, this article has the details for future reference (not relevant to you now): Refresh Firefox - reset add-ons and settings.

I have always had "show hidden files and folders" enabled.

My opinion is that you are correct regarding avast! performing cranial surgery on my Firefox profile. Additionally, some minor non-Firefox settings were modified. I am not seeking your response on the latter since they are not related to Firefox, but I cannot locate Notepad on my primary Start menu; I must go to Accessories. Therefore, my screen name of "Dead_Man_Thinking" is quite appropriate.

I can save new bookmarks successfully. I presume that at this point I have no choice but to commence resaving all my bookmarks manually, correct?

Here's one other possibility. Windows' system restore feature may have stored a version of places.sqlite in a restore point. To check for that, you can use the "Previous Versions" tab in the file properties dialog. You probably are familiar with much of the following, but just in case:

You can open your current Firefox settings (AKA Firefox profile) folder using either

• "3-bar" menu button > "?" button > Troubleshooting Information
• Help menu > Troubleshooting Information

In the first table on the page, click the "Show Folder" button

This will launch a Windows Explorer window shows your current settings files. Scroll down to places.sqlite, right-click, Properties, then the Previous Versions tab. This should show whether there are any files to restore. However, before actually restoring any older versions, make sure to exit Firefox and allow enough time (15 seconds should do it) for it to complete file updates, otherwise the restored file may get corrupted.

If there are no previous versions whatsoever, this may not be your original profile folder. avast! may have deleted it, or you might be in a parallel folder. If you click up a level to the Profiles folder, do you see any other folders here other than your currently active one?

If avast! deleted the folder, you might be able to use system restore selectively for old Firefox data, but since I generally avoid this feature, I am not the best person to describe how to dig around in the available files to fish out the last places.sqlite.

https://support.mozilla.org/en-US/kb/restore-bookmarks-from-backup-or-move-them?esab=a&s=bookmarks+backup&r=0&as=s

Restore bookmarks from backup or move them to another computer Learn how to restore your bookmarks from the automatic backups that Firefox creates, save and restore your own backups, and move bookmarks to another computer.

There are no files to restore:

Import and Backup > Restore > Monday, June 9, 2014 (14 items).

That backup occurred AFTER my bookmarks disappeared. There are no other backups appearing.

jscher2000,

Previous Versions tab: "There are no previous versions available."

I cannot use Windows Restore because my PC will not create the DVDs for that function, but the CD/DVD reader/writer works perfectly for everything else.

However, I wish to thank you for your excellent detailed information. All that you stated about accessing Firefox settings was unknown to me previously.

Hi Dead_Man_Thinking, just to be clear, I do not mean to suggest doing anything drastic with Windows, just to try to dig into any system restore points Windows might have created in recent weeks.

As noted above, I am not very familiar with this feature, so you could seek advice on other forums. Perhaps something like the following program might be useful to see whether a copy of your old profile folder is there somewhere: http://nicbedford.co.uk/software/systemrestoreexplorer/ (I haven't tried it myself).

This is for later. These add-ons will help you by making backups of your stuff. And in the event of trouble, can restore everything back.

FEBE (Firefox Environment Backup Extension) {web link} FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backup of files that you choose.

OPIE {web link} Import/Export extension preferences