There are several ways to manage this.

• Back up the profile.
• Create a sync account, which is another backup. and it backs up add-ons but not dictionaries.
• Exit Firefox 133.
• Use the command firefox -P. Rename the old profile to profile.old
• Uninstall 133 and install 130. Create a new profile with the desired name, and re-sync.

Long ago, I was thought in the Firefox kindergarten that these were the important files.

User added: /chrome & contents user.js

Firefox: cert9.db cookies.sqlite favicons.sqlite formhistory.sqlite handlers.json key4.db logins.json permissions.sqlite persdict.dat places.sqlite search.json.mozlz4

You can also copy them over to the new profile. But keep the original.old untouched. If missing the bookmarks, refresh (rebuild) the new profile from about:support.

Why Firefox 130? As you probably know, Mozilla discloses security vulnerabilities when it releases an update, so there are known issues with that version which expose you to higher risk.

If you decide to proceed anyway:

(1) Download safely. See: Install an older version of Firefox

(2) Migration might be easier, but isn't guaranteed to be successful, using the "allow-downgrade" option mentioned near the end of the following article: Dedicated profiles per Firefox installation

For reference, this is from your downgrade to Firefox 131: https://support.mozilla.org/questions/1476231

There are several ways to manage this.

• Back up the profile.
• Create a sync account, which is another backup. and it backs up add-ons but not dictionaries.
• Exit Firefox 133.
• Use the command firefox -P. Rename the old profile to profile.old
• Uninstall 133 and install 130. Create a new profile with the desired name, and re-sync.

Thanks for the reply. A few questions:

How do I sync an account? (I don't believe I have a FF account, at least with a username & pwd) How & where do I use the command firefox -P?

Thanks again.

Why Firefox 130?

I actually meant v131.0. Could not change after posting.

Why? Because every version of FF after v131.0 is so buggy on many of the pages I use, especially Ebay, Facebook and Youtube. I had no issues using v131.0. I'm not as concerned with security as I am with functionality.

My previous post was what happened the last time I tried to downgrade. I'm trying to avoid the same situation.

jscher2000 - Support Volunteer said

Why Firefox 130?

Because every version of FF after v131.0 is so buggy on many of the pages I use, especially Ebay, Facebook and Youtube.

What kind of bugs?

My previous post was what happened the last time I tried to downgrade. I'm trying to avoid the same situation.

Okay, other than the compatibility.ini solution there, refer to the allow-downgrade option.

ineuw said

There are several ways to manage this.

• Back up the profile.
• Create a sync account, which is another backup. and it backs up add-ons but not dictionaries.
• Exit Firefox 133.
• Use the command firefox -P. Rename the old profile to profile.old
• Uninstall 133 and install 130. Create a new profile with the desired name, and re-sync.

Thanks for the reply. A few questions:

How do I sync an account? (I don't believe I have a FF account, at least with a username & pwd) How & where do I use the command firefox -P?

Thanks again.

Ladies and gentlemen of the highly esteemed Mozilla support group ! I consider your responses are somewhat callous.

The poster's comments are valid. I am monitoring the differences between eight GENERIC installations of Firefox in Linux within the same version ranges, and attest that similar problems exist on Wikipedia and Wikisource. These issues do not exist in the Google Chromium family of browsers, Both of which I use for immediate comparison !

firefox -P is used in a terminal. and you have to create a firefox account to sync.

ineuw said

There are several ways to manage this.

• Back up the profile.
• Create a sync account, which is another backup. and it backs up add-ons but not dictionaries.
• Exit Firefox 133.
• Use the command firefox -P. Rename the old profile to profile.old
• Uninstall 133 and install 130. Create a new profile with the desired name, and re-sync.

Thanks for the reply. A few questions:

How do I sync an account? (I don't believe I have a FF account, at least with a username & pwd) How & where do I use the command firefox -P?

Thanks again.

Firefox Accounts have been renamed as Mozilla Accounts since early November 2023.

You are using a Mozilla Account to post here on this support.mozilla.org site and is used for Firefox Sync

How to start Firefox with the ProfileManager as you use the firefox.exe -P method while Firefox is completely shutdown and not running. https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles