This article tells you what files to recover from the old profile. https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

4. I have followed archived support help steps for this issue but did not restore previous Firefox profile.

What did you try so far? Do you have a link to the post you followed?

Here's what I usually suggest (modified for Mac OS so possibly some parts could be unclear):

(1) Open Source Old Firefox Data Folder

Open that Old Firefox Data folder in Finder. Do not drill down into any subfolders.

Resize that Finder window with the source folder and move it to the left side of the screen.

(2) Open Destination Profiles Folder

In Firefox, type or paste about:profiles in the address bar and press Return to open that page. You may have more than one profile listed, but presumably they are all in the same location. In the Root Directory row under one of the profiles, click the Open Folder or Show in Finder button.

Check the Finder address bar (does it have an address bar?). If the folder has a weird name, navigate "up" or "left" one level so you are looking at the contents of the Profiles folder.

Resize that Finder window with the destination folder and move it to the right side of the screen.

(3) Drop a copy of the old profile folder back into the folder Firefox uses for profiles:

In the source Old Firefox Data folder on the left, select the weirdly profile folder and run File > Duplicate to create a copy of the folder.

Drag the copy to the destination Profiles folder in the Finder window on the right side of the screen and drop it in the blank space there.

Remove "Copy" from the name of the folder you dropped in the Profiles folder. To start renaming, you can click the folder and either press Return or click in the folder name. Once the folder name matches the original, you're done.

(4) Configure Firefox to use the old profile

Make a note of the text after the dot on the profile folder. For example, it might be default or default-release. You need the new profile name to match the old one in order for Firefox to regain use of your extensions and their data.

Inside Firefox, return to the about:profiles page.

• Click the "Create a New Profile" button, then click Next.
• Assign the old profile name (for example, default or default-release) and Firefox should show a proposed folder name with a new random part.
• Click the "Choose Folder..." button and select the folder you dragged-and-dropped so that Firefox picks up the full old name.
• Back in Firefox, click the Done button.

After creating a new profile, Firefox usually makes it your default profile (for external links and the next startup). To test, scroll down to it and click the Launch profile in new browser button.

Did it work?

If so, you're done.

If not, you can close that window without affecting your regular Firefox profile and change back to the profile you started with before this post. Click the Set as Default Profile button below that profile.

At step (2) I have the Old Firefox Data window open and I have created a copy of the profile file. However in the Profiles window that profile name from the Old Firefox Data folder already exists there, so there is no point in transferring the copy there.

I am stuck at this step in the process.

This article tells you what files to recover from the old profile. https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

This link does not explain how to import the profile from the Old Firefox Data folder (on the desk top) to the new profile created after the Refresh.

After the Refresh Firefox behaves as a new install. There is no profile in the new Firefox with the previous history, bookmarks, and password data.

At step (2) I have the Old Firefox Data window open and I have created a copy of the profile file. However in the Profiles window that profile name from the Old Firefox Data folder already exists there, so there is no point in transferring the copy there.

Okay, I guess you copied it over earlier if there's an exact match? Try step (4) now.

terry21 said

This article tells you what files to recover from the old profile. https://support.mozilla.org/en-US/kb/recovering-important-data-from-an-old-profile

This link does not explain how to import the profile from the Old Firefox Data folder (on the desk top) to the new profile created after the Refresh.

After the Refresh Firefox behaves as a new install. There is no profile in the new Firefox with the previous history, bookmarks, and password data.

If you choose this method, you would replace selected files in your currently selected default profile with files from your pre-Refresh profile. You can determine which profile is your current default from the list on the about:profiles page -- the profile that Firefox is currently using will have this:

This is the profile in use and it cannot be deleted.

Of course, you need to Quit Firefox before deleting or replacing any files in the active folder.

I've made progress based on the above and sort of have it working now. What I haven't been able to work out is, how do I restore the last Firefox session that was open before it was refreshed? I had a lot of tabs open with on-line documents that I was intent on reading and I'd really like to be able to restore all of those. How can I recover all the tabs which were open when Firefox was refreshed? I can see the browsing history does go back a long way before the refresh.

Do you want to restore the old session automatically in place of your latest one, or have a list of the tabs for reference?

When Firefox exits normally, it creates a sessionstore.jsonlz4 file at the main level of your profile folder, and updates the sessionCheckpoints.json file (they appear next to each other). In your old profile, do you have those two files? If you already copied over those files (while Firefox was closed), then at the next startup, that session should be available under either:

• "3-bar" menu button > History > Restore Previous Session
• (menu bar) History > Restore Previous Session

If they are missing or grayed, Firefox might already have restored the session. Check for additional windows under either:

• "3-bar" menu button > History > Recently Closed Windows
• "Library" toolbar button > History > Recently Closed Windows
• (menu bar) History > Recently Closed Windows

If you don't have any closed windows there, either Firefox didn't process the file or there is a problem in the file.

If Firefox did not exit normally, the last snapshot of your session would be in the sessionstore-backups folder along with other snapshots:

• recovery.jsonlz4: the windows and tabs in your currently live Firefox session (or, if Firefox crashed at the last shutdown and is still closed, your last session)
• recovery.baklz4: a backup copy of recovery.jsonlz4
• previous.jsonlz4: the windows and tabs in your last Firefox session
• upgrade.jsonlz4-build_id: the windows and tabs in the Firefox session that was live at the time of your last update

You might be able to judge from the date/time stamps on the files which one would be most useful.

I have a tool to preview the file contents and convert it to a list of clickable links. You would drag and drop one of the files onto the large box on the following page, then click the "Scrounge URLs" button:

https://www.jeffersonscher.com/ffu/scrounger.html

If you don't get a list within 15 seconds, that probably means the script is caught in a loop. You may need to close the tab to avoid a tab crash and then try again in a new tab.

If you get a useful list, use the Save List button to archive it as a web page of clickable links for future reference, in case no other approach is successful.