First things first. Congratulations on your new iMac. Must be awesome.

Unfortunately, I don't know much about Firefox remembering open tabs. I can offer two ways to get this done you might already know well, but in case this helps...

With the recent release of version 80x, the FireFox synch process changed significantly. The basic concept is to pair the FireFox installations on the two devices, which will cause them to sync with one another. I have laid out steps for doing this below, which will transfer the open tabs on your old iMac to your new one.

The other way I can suggest is to save your tabs to a folder of bookmarks, export the bookmarks to an html file, copy the file to the new iMac, import the bookmarks, then open the folder of bookmarks to tabs.

Both processes start the same way, which is saving the tabs to a folder of bookmarks, exporting the tabs to html file. This file can be copied to the new iMac and it also serves as a backup in case something goes wrong somewhere.

To make the bookmark file... 1. Open all the tabs in FireFox on old iMac 2. Click Bookmarks in the FireFox menu, then select "Bookmark all Tabs". That will create a folder of bookmarks containing all your open tabs. 3. Again under Bookmarks menu, Show All Bookmarks. 4. Near the top of the window that opens, the rightmost icon will be up and down arrows... click that. 5. Select "Export Bookmarks to HTML..."

COPY THE HTML FILE TO NEW IMAC TO TRANSFER OPEN TABS When you finish the export, you will have a file you can copy to your new iMac, then import by going to Show All Bookmarks in FireFox, clicking the icon with the up and down arrow near the top, then select "Import Bookmarks from HTML..." After importing the bookmarks, you can find the folder with all your open tabs, and open all the bookmarks in that folder by right clicking on the bookmarks folder in FireFox, then select the top option "Open All in tabs"

USE FIREFOX SYNC INSTEAD OF COPYING FILE This is an alternative to file transfer described above.

Backing up the bookmarks to an html as described above is important, in case you blow your tabs away through a botched synch effort. Once you have the backup file...

You can transfer open tabs using sync instead of copying the file from the old iMac to the new one.

On old iMac 1. Verify the machine is running FireFox v80x or later. Update FireFox if necessary. 2. In FireFox, tap the three little horizontal bars in the upper right corner to open the FireFox menu, select Preferences-> Synch. 3. Login to Firefox with a FireFox account. If you don't have one already, make one. 4. On the same preferences-> synch screen, check the boxes for the elements you want to synch between devices. In this case, you will include "Open Tabs". 5. Still on the sync page, click the link at the bottom that says "Connect another device" That will bring up a page with an instruction to signin to FireFox on another device. 6. Leave old iMac running, as you continue to your new iMac.

On new iMac 1. Install FireFox, verifying the version is the same as the one running on your old iMac 2. In FireFox, tap the three little horizontal bars in the upper right corner to open the FireFox menu, select Preferences-> Synch. 3. Login to Firefox with the same FireFox account running on old iMac

Once you get this far, instructions will start appearing on the machines that will be a better guide than any steps I can provide in detail at this point. The basic concept is you will be pairing the devices. You will have an option to scan a QR code displayed on your old iMac with a camera attached to your new iMac, or use email to validate the pairing. Once you pair them, they will synch with one another. I have no idea how FireFox knows to synch both machines to the tabs and other items you select for synch based on your old iMac instead of your new one, but I can tell you that if you go through the process in the order I explained (i.e.,, starting with your old iMac), the settings on your old iMac will be transferred to your new one. I have done this with bookmarks but not open tabs.

There is a good chance someone else will be able to post a shorter, simpler answer to your question. If you have any questions about what I have posted here, please do not hesitate to ask.

Hi tencosp, I'm old fashioned and tend to copy files from one place to another.

One think I can mention is to back up your currently active Firefox profile folder. This article has suggestions on that: Back up and restore information in Firefox profiles.

You also can archive your session details as an HTML document of clickable links. Obviously that's not as convenient as having all your tabs opened automatically for you, but in case lightning strikes, it's something you can email yourself so you don't lose it. Here's how:

(A) Open your current Firefox profile folder using either

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

In the first table on the page, on the Profile Folder row, click the "Show in Finder" button.

If Finder highlights an icon with a semi-random name like a1b2c3d4.default, double-click it to display the contents of that profile folder.

At this point you should see the sessionstore-backups folder. Double-click into that folder and you should see files like recovery.jsonlz4 (your live session history file), previous.jsonlz4, and various session snapshots made during updates.

Keep this Finder window open, size it so it's small enough to see the Firefox window, and switch over to Firefox.

(B) Open this page on my website:

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

(C) Drag and drop the recovery.jsonlz4 file from Finder onto the box in the page. A script in the page should decompress the file and show its contents in the text box.

If this doesn't complete in 15 seconds, the script may have crashed. You can close the page and start at B again.

(D) Click the Scrounge URLs button to generate a page from its contents.

If this doesn't complete in 15 seconds, the script may have crashed. You can close the page and start at B again.

Click the Save List button to keep a local copy of the list as an HTML page of clickable links.

You can close this tab now.

Thanks!

Note that it its still better to bookmark these tabs to have a secondary backup in case something goes wrong with session restore or if you accidentally close windows in the wrong order as on Mac you can close all windows, but still have the Firefox application running with the menu bar visible.

Firefox uses two locations for the Firefox profile folder, so make sure to look in the correct location. Location used for the main profile that keeps your personal data (Root Directory on about:profiles).

• ~/Library/Application Support/Firefox/Profiles/<profile>/

Location used for the disk cache and other temporary files (Local Directory on about:profiles; no need to backup).

• ~/Library/Caches/Firefox/Profiles/<profile>/

Thanks to everyone who replied. It turns out that I didn't have to do anything. When I migrated my old iMac to my new iMac using my TimeMachine backup, the migrated version of Firefox remembered the open tabs as well as all other settings.

You can always send tabs to other devices.

Just have both computers logged in on your Firefox account. Then click on the three dots on your search bar (view the image I provided) then click on "Send tab do Device" and click on your new computers name and it should transfer it smoothly.

You can also send tabs to your phone or any other device that is logged in to your account.