There is a mismatch between the profiles.ini file, listing the location of your default profile folder, and your actual profile folders. This could occur if a Refresh stalled or was interrupted.

To get started, if Firefox is installed, call up the Profile Manager and create a new profile. Here's how:

Note: A new profile will have your system-installed plugins (e.g., Flash) and extensions (e.g., security suite toolbars), but no themes, other extensions, or other customizations. It also should have completely fresh settings databases and a fresh cache folder.

Type or paste the following into the Windows 7 Start Menu search box, and press Enter to run it:

firefox.exe -P

Don't delete anything here!

Any time you want to switch profiles, exit Firefox and return to this dialog.

Click the Create Profile button, assign a name like Jan2018, and skip the option to relocate the profile folder. After creating the profile, select it and start Firefox in that profile.

Up and running?

Next step will be to see what profile folders you have around and figure out which one you want to mine for old data/settings.

Next, let's go looking for old profile folders:

Did Firefox perform a Refresh?

Unless it was interrupted in progress, you should find a folder on your desktop named Old Firefox Data. Inside would be a semi-randomly-named folder with freshly updated files. Does this look like your most recent data?

If so, we'll suggest how to rescue key files or completely restore the earlier profile folder.

If not...

Does the internal Profile Manager list your immediately previous profile folder?

To check on that, inside Firefox, type or paste about:profiles in the address bar and press Enter/Return to load it.

This page should list all the profiles Firefox is currently aware of. If you see a profile that is not currently set as default that looks promising, scroll down to it and click the Set as default profile button below that profile, then scroll back up and click the Restart normally button. (There are some other buttons, but I think those are still "under construction" so please ignore them.)

Firefox should exit and then start up using the other profile. Is that the right one?

If it's not there...

Did Firefox orphan your old profile folder?

Here's how to check whether there are additional profile folders in the standard location in addition to the one you're using. Start by opening your current Firefox profile folder using either:

* "3-bar" menu button > "?" button > Troubleshooting Information
* (menu bar) Help > Troubleshooting Information
* type or paste about:support in the address bar and press Enter/Return

In the first table on the page, click the "Open Folder" button, to launch a new window listing various files and folders in Windows Explorer.

In the Windows Explorer address bar, click the capitalized word Profiles to move up one level in the folder hierarchy. More than one folder here by any chance? Do the files in those folders look like they were last updated around the time of the update?

If you've got any promising looking folders, we can discuss next steps to recover use of them.

rogelio4107 said]

Jscher2000, thanks for your suggestions. As I can't get into firefox to do these, can I delete all firefox programs, folders, data, etc and start new download as though I haven't used it before? It seems this may be most direct way at this point. Thanks.

You should be able to use the first reply, Start menu search box:

firefox.exe -P

Does that work?

If not, you can try renaming your data folder (to avoid losing all your old data, I suggest renaming instead of deleting). Here's how:

In the Start menu, search box, paste this and press Enter:

%APPDATA%\Mozilla

That should launch a new Windows Explorer window here:

C:\Users\your-user-name\AppData\Roaming\Mozilla

In this folder, right-click > Rename the folder Firefox to Firefox-OLD

Then when you start Firefox, it should set up a new Firefox folder.

Success so far?

You do not have any non ASCII Unicode characters in the path to your Windows user account?