Hi, you can ignore the Bookmarks Toolbar setting, since that refers to the horizontal bar below the main toolbar, not the sidebar.

This is a bug in Firefox 138 caused by data stored in a settings file. It will be fixed in Firefox 140, but for now, the workaround is to switch to the classic sidebar and remove a settings file. This assumes you do not need to use the new tabs-in-sidebar feature.

(1) Switch back to the Classic sidebar if you have the new design. The new design has a button bar at the left of the browser. Here's how:

On the Settings page, slowly type side into the tiny search box to filter the listed settings. This should bring the "Browser Layout" section to the top.

Un-check (clear) the checkbox for "Show sidebar". That should remove the launcher.

Then press Ctrl+B to open the classic Bookmarks Sidebar.

(2) Remove the xulstore.json file from your current profile folder. Here's how:

Open your current Firefox settings (AKA Firefox profile) folder using either

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

In the first table on the page, on the Profile Folder row, click the "Open Folder" button. This should launch a new window listing various files and folders in Windows File Explorer. (On Mac and Linux, the button is labeled a bit differently.)

Leaving that window open, switch back to Firefox and Exit, either:

• "3-bar" menu button > Exit
• (menu bar or Alt+F) File > Exit

Pause while Firefox finishes its cleanup, then:

Right-click xulstore.json then Rename to something like xulstoreOLD.json

Start Firefox back up again and show the Bookmarks Sidebar using Ctrl+B. Now it should stay open when you exit/restart Firefox.

To restore optional bars, see:

• Bookmarks Toolbar - Display your favorite websites at the top of the Firefox window
• Restore the Menu bar in Firefox
• Title bar: Customize Firefox controls, buttons and toolbars

When I go to the settings page, 'Show Sidebar' is already unchecked. Should I still do your Step 2?

While waiting for your reply, I thought I'd check out those Step 2 instructions just in case I had more questions.

I am using a Mac, so I have the link 'Show in Finder' in the 'Profile Folder' line, so I'm thinking that's correct, as you said the button is labeled a bit differently.

When I click that button, the Profile folder opens, with 5 folders in it. When I open them, each one has a file named xulstore.json. Assuming I've found the right file(s), do I rename all of them?

My 3-bar menu doesn't have anything labeled 'Exit.' And a Mac doesn't use 'Alt'. Can I just click the red x to shut down Firefox? Or is there some Mac command that will stand in for the Alt-F? Because Command+F is for Find.

Yes, keep the box un-checked. And as you know, use Command+B instead of Ctrl+B to open/close the sidebar.

For Finder, when you first click Show in Finder, the active profile folder may be highlighted. If not, refer back to the Troubleshooting Information page for the current profile name. (I haven't used a Mac for 6 years, so it's hard to keep up with how it works.) You only need to rename the one Firefox is currently using.

Instead of Exit, use Quit. Either:

• menu button > Quit
• (menu bar) Firefox > Quit

The reason for using Quit on Firefox for Mac is that Firefox can linger in the background when you close individual windows.

It worked perfectly. Thank you for your time and also for making the instructions so simple to understand.