For full context, I'm going to copy/paste from another thread and you can tell me if this is the procedure you tried:

Background

Yahoo changed its toolbar Monday:

On August 1, 2016 we will simplify the Firefox Yahoo Toolbar and upgrade your browser to the New Tab by Yahoo extension experience. This extension provides a static version of Yahoo Toolbar and customizes your new tab page with Flickr photos and quick access to your top sites. Please note, you will no longer be able to modify your toolbar layout.

Source: https://downloads.yahoo.com/faqfirefoxtoolbar

Unofficial Roll Back Procedure

Here's how I suggest going about it:

(1) Remove the new toolbar on the Add-ons page. Either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then on the right side find and remove the Yahoo extensions. These may include:

• Yahoo! Toolbar and New Tab 5.0.2 -- version numbers visible when you click the More link below the extension's title
• Search and New Tab by Yahoo 1.0.6

Often a link will appear above at least one disabled/removed extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

(2) Install version 3.2.18.20160725095733 -- the July 26th version -- of the toolbar from the following page:

https://addons.mozilla.org/firefox/addon/yahoo-toolbar-and-new-tab/versions/ -- it's currently the second one down

Before restarting Firefox, go back to the Add-ons page, click the More link under the Yahoo Toolbar extension, and turn off automatic updating. (In case you closed the page...)

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Find Yahoo toolbar on the right side and click the tiny More link under the title, then on that page, find the row for Automatic Updates and set it to Off.

Then you can use the restart link for the toolbar to complete the installation.

Success?

I followed the procedure for getting the old toolbar back, but when I went into the list of versions, version 3.2.18.20160725095733 was not available. None of the other versions restored my original toolbar. What can I do to get it back?

They took it down at some point and there's no official point of distribution that I know of.

If you make regular backups of your system, possibly you have an old copy of your profile folder (and within it, the extensions folder) from around that time which might contain the earlier version of the extension.

Alternately, you could look for the extensions folder in a Windows restore point from around that time. To facilitate that, you could try this program:

http://nicbedford.co.uk/software/systemrestoreexplorer/

Thank you for the info. I did a system restore and got it back. All is good, but what a pain. They need to fix this problem for those of us who prefer the old version with all our bookmarks.