GBinHoosick, some files within the profile can rely on absolute paths. Add-ons for example can do this. Hence they will be looking for resources in locations that were correct for the path where they were installed, but may not exist anymore.

Here is a help article showing a table of files and their purposes (although cor-el may have covered them all already). https://support.mozilla.org/en-US/kb/about-your-important-data-and-their-files

You do not need to copy any additional files with variants of the given names.

Yes, overwrite any pre-existing files in the new profile folder to replace the data with the original set. But obviously make a copy of the new profile folder first, if you think its possible that you may wish to use it in the future as it originally was.

Thanks, TechHorse, that's very helpful.

In reading and thinkiing further, I'm wondering if an alternative "best" way to accomplish this would be to use the "restore with a backup file" procedure described here: [https://support.mozilla.org/en-US/kb/firefox-backup]? According to that article:

The backup file saves browsing data, such as:

Bookmarks Settings History Passwords Payment methods Extensions Other browsing data Sensitive data such as passwords, payment methods, or credit card numbers is encrypted and protected by a password.'

You can choose to back up:

Basic data, and you won’t have to use a password.' All data, including sensitive data, but you’ll have to use a password. When you install Firefox on a new device, you can restore all your browsing data.'

That would seem to be all the key data needed to get my new Firefox install looking just like my old one, but seemingly doesn't copy all folders, files, etc. in the possibly corrupted and certainly "tired" old profile folder, and also avoids the relative hassle of copying and pasting the correct files -- and only the correct files -- from the old folder.

What do you, and any other kind contributors, think? I would be particularly thrilled and honored if cor-el was to participate!!!!! .... not that I'm in any way minimizing your help, TechHorse.

I was impatient to get Firefox set up on my new computer, so I took the plunge, using the "restore with a backup file" procedure, and ..... HUGE SUCCESS!!!! It appears that EVERYTHING important was restored to the new FF profile on the new computer, including all my passwords (so important!), settings, extensions, etc. And, with this new profile, FF is unbelievably speedy, opening and closing virtually instantaneously, whereas on my 9 year old previous computer, with an FF profile that was even older than that, it took many minutes to open! Part of that no doubt is because my new computer is a Beast (core 7 CPU, 32 GB RAM, etc.) and is multitudes faster than my old one, but much/most of it is probably due to how buggy my "old" FF profile had become.

I'll keep snooping around to see if everything was restored correctly, and report here if I find otherwise. For now, though, my recommendation to anyone looking to transfer key FF data to a new profile and/or device is to feel confident in using the "restore with a backup file" process. It's easy, fast and works!!!!!

Signed, A Happy Camper 😊

GBinHoosick, glad that you found a suitable way. The new inbuilt backup system is no doubt the easiest method for most users.

Just to answer your question anyway, I don't think that you can go wrong with also copying the entire original profile folder as well as using the internel backup system.

Then you have all three options available to you in case something goes wrong with one of them.

1. Restore from the backup file.
2. Restore the entire original profile folder.
3. Restore selected individual files from the original profile folder.

But admittedly the second two methods are more for advanced users and hopefully the first option will just work anyway.

Thanks for the reply and ongoing interest, TH. Yup, it's always nice to have several options.

BTW, I've looked around enough to be certain that everything did transfer and restore perfectly to my new FF profile and install. I'm so pleased, because I've been using FF for decades, and have really built up a huge amount of data (e.g., 281 saved passwords, hundreds of bookmarks, etc.) and customizations, and to get that all back in what was essentially a one-click process (after moving the backup file to my new computer and installing FF) is FANTASTIC.

Great work by Mozilla folks to recently add the "restore from backup file" procedure! I'm really liking the new free VPN (up to 50 GB/month) feature in the newest FF version, as well.

Hi,

Glad to hear that you've been able to transfer the data successfully! I've marked your reply above (mentioning Firefox Backup) as a solution to highlight it for other users. Thank you for sharing your experience here!