Norton killing Firefox

Thanks for the info. When you removed Norton did you use the removal tool and perform a "remove only" scenario following this guide and scrolling down to the section named "I need help removing Norton"? If not perform that. Also remove FireFox at the same time since it may also be corrupted. The reasoning is that if you have "fast startup" enabled on Windows 10 it is suggested to disable it. Having it enabled doesn't allow the system to perform a 100% data release on reboots. Which in turn, can cause data corruption. Here is how. Make sure you reboot before reinstalling your norton product from your norton account.

Cheers

I would suggest removing version 74 and rebooting. Install FF version 73 following this article.

Cheers

Norton Security
22.19.9.63
Windows 10 Pro
17763.1.amd64fre.rs5_release.180914-1434
Norton Autofix Results: 0 item(s)

Hi Entrepreneer :

Please check your current Norton version at Help | General Information | About to see if a recent Automatic LiveUpdate has delivered the latest v22.20.1.69 (see the 27-Jan-2020 product update announcement Norton Security 22.20.1.69 for Windows is Now Available!).  If you have been using an older Norton product it's possible you were recently forced to upgrade to 22.19.9.63 (see the 08-Mar-2020 announcement Active Customers in Legacy Versions are Being Upgraded) and still haven't received the v22.20.1.69 product update. Let us know if you received one of these forced upgrades and we'll provide instructions for performing a clean reinstall, since a quick refresh using the Norton Remove and Reinstall tool in regular "Reinstall" mode might not be enough to fix your problem if the forced upgrade corrupted your Norton installation.

Just another thought, but am I correct that you have installed the optional Windows 10 version 1809 build 17763.1131 (KB4541331, released 17-Mar-2020) (see the TechSmith article How to Check Windows 10 Build if you aren't sure how to find your version and build number)? If so, do you normally run manual Windows Updates to seek out optional beta updates that are released outside of "regular" Patch Tuesdays on the second Tuesday of the month (note that the March 2020 Patch Tuesday updates on 10-Mar-2020 should have automatically delivered KB4538461 / Build 17763.1098 if you have Win 10 v1809), and is this the "sizable" Windows update you mentioned in your 22-Mar-2020 post <here>?  I am not sure if any new bugs have been reported for this optional KB4541331 / build 17763.1131 that might cause problems with Firefox or Norton but we can investigate further if this is your current build and a clean reinstall of Norton can't fix your problem. And just an aside, but also note that your Professional edition of Win 10 v1809 is reaching end of support in a few months on 12-May-2020 (see the Windows 10 Lifecycle Fact Sheet) and will need to be upgraded soon.

Entrepreneer:
...The same day I put Norton on this device, I was hacked - accidentally downloaded a Trojan, realized it immediately and decided to load Norton. That's when the Norton trouble began, but the attack had already been made. Attacks have shown in two bank sites and Facebook, so far. So now, in addition to getting Norton working, I'm in damage control.

In another thread I saw Malwarebytes recommended, so today ran that, removed 4 trojans and something else, maybe a popup...

Hi Entrepreneer:

Could you please clarify?  Are you saying that you were infected by multiple trojans that were missed by Windows Defender, you then installed Norton and ran a Full System Scan scan that did not detect any threats, and then installed and ran Malwarebytes v4.x which found 4 trojans missed by both Windows Defender and Norton?  Did you disable the 14-day trial of the Malwarebytes Premium real-time protection and use Malwarebytes Free as an on-demand scanner and so it doesn't interfere with Norton's real-time protection (see my post in msfitnsoo's Full Scan detected : W32.Mparty/W32.Klez.H/JS.Yamanner)?  If you're certain that Malwarebytes detected 4 trojans (not lower-risk PUPs / potentially unwanted programs like adware, browser hijackers, etc.) missed by both Windows Defender / Norton (and you're certain these weren't low-risk detection like adware, browser hijackers, etc.) then I would suggest that you post in the Malwarebytes Windows Malware Removal Help & Support board (see the posting guidelines <here>) so their malware removal specialists can looks at your Threat Scan log and other diagnostics to ensure your computer is not infected.

...My Norton Security is v22.20.1.69... My Windows 10 version is 1909 build 18363.720, looks like I don't reach end of service for another 14mo. I don't look for updates manually, and didn't realize they did patches on predicted days. Apparently I have a cumulative patch,this month, KB4541335.

Are the specs in your original post <here> a copy and paste from an old AutoFix scan?  They seem to indicate you have Win 10 Pro v1809 build 17763.x.  Also note that the latest Norton v22.20.2.57 started rolling out on 25-Mar-2020 per the product update announcement Norton Security 22.20.2.57 for Windows is now available! so if Help | About shows you still have v22.20.1.69 you should re-boot and run a few manual LiveUpdates to see if v22.20.2.57  fixes your problem.  Like most product updates, v22.20.2.57 is being released in a phased manner, and once it's pushed out it might require a few cycles of re-booting and LiveUpdates before your Norton product is completely updated to the latest version.

....I am basically where I started: FF will not open at all, except from the Norton help window. ... Once open, FF (although I haven't sync'd yet) recalls my bookmarks and log-ins.

I don't understand.  Do you mean that you must launch Norton and go to Help | About before you can open Firefox?

Did you follow the instructions in the Mozilla Firefox support article Troubleshoot and Diagnose Firefox Problems when you performed your reinstall and browser refresh?  If you performed a browser refresh (Step # 5) correctly it should have removed most of your browser add-ons and cleared your custom configuration settings but your bookmarks and browsing history should not be removed, even if you store all your personalized settings locally and don't use Firefox Sync to sync bookmarks, add-ons, etc. between devices. Only the creation of a clean Firefox user profile (Step # 6) should wipe all your local settings, including your bookmarks and browsing history.

...Thank you, based on your post I tried:

1. Uninstall Norton using the removal tool;
2. disabled fast startup;
3. reset FF to original (I can sync for bookmarks etc, once this is sorted);
4. reinstalled Norton ...

Did you uninstall Norton by running the Norton Remove and Reninstall (NRnR) tool in normal "Reinstall" mode, or did you perform a clean reinstall (which includes running the NRnR tool in advanced "Remove Only" mode as one of the steps) to wipe Norton off your system before the manual reinstall?  See the general steps <here> for performing a clean reinstall.

2020 03 17 – discovered theft from one bank account (had occurred on the 12th); began damage control.
2020 03 20 – other bank discovered attempted credit card abuse, contacted me....

2020 03 28 – discovered Facebook attack; still in damage control; warned all my friends!

Hi Entrepreneer:

Be sure you've contacted every banking and financial institution you deal with to inform them about this identity theft and ensure all your credit and debit cards have been cancelled.  Also ensure the sign in passwords for any financial site you log into to (including online shopping sites like Amazon, etc.) are changed.

This is a serious malware infection you are dealing with. I don't know if the email you received from your friend was a phishing scam that directed you to a fake website where you entered your credit card information and/or login password for your bank's web site, but if it also managed to plant a backdoor trojan on your system it's dangerous to assume that Malwarebytes has cleaned the last traces of this infection off your system.  Instead of waiting for the latest Norton v20.22.2.57 update I would strongly advise that you immediately post in the Malwarebytes Windows Malware Removal Help & Support board and request the assistance of a trained malware removal specialist, since their posting guidelines I'm Infected - What Do I Do Now? note that it can sometimes take up to 48 hours before your diagnostic logs are reviewed.  If you have the Norton Safe Web browser extension installed in your browser then I'd also check to make sure that Banking Protection is enabled in that extension, although that probably won't help if they've already stolen your credit card information and/or login passwords for your banking sites.  See the support article FAQ: Online Banking Protection for more information about this feature.

There are a handful of other reputable malware removal sites you can post in to receive one-on-one assistance from a trained malware removal specialist (I've used both the BleepingComputer and WhatTheTech sites reviewed in delphinium's 2013 thread Malware Removal Forum Recommendations in addition to Malwarebytes) but the Malwarebytes site probably makes more sense in this case given that your Malwarebytes Threat Scan report contains relevant information about the trojans that were (or still are) infecting your system.  If you request assistance pick one site only and don't cross-post about the same problem in multiple malware removal forums.

2020 03 12 – accidentally downloaded the trojan (via email from a friend); yes Defender allowed it in, but then may have prevented it from fully opening.
Loaded Norton Security; it ran a scan & reported "suspicious activity" and recommended a deep clean, but warned me this would be more invasive. I did not opt for that.
(for the answer on Malwarebytes, pls see 2020 03 29)

2020 03 13 – uninstalled Norton security, as it seemed to have killed Firefox (I had allowed one or two, not all, of the add-ons, and then assumed these were the problem; I had not yet concluded the downloaded trojan file had actually created any trouble). After uninstalling Norton, FF started working normally. I saw no other problems.

There might still be some information in your Norton security history (e.g., Resolved / Unresolved Security Risks or a high number of incoming / outgoing blocks in your Firewall Activities) that could indicate an active infection - see the support article Monitor Security Tasks Using Security History.  If you ran the Norton Remove and Reinstall tool in advanced "Remove Only" mode just note that this probably wiped your past security history so there might not be any useful information there now.

It's quite possible that uninstalling Norton Security on 13-Mar-2020 gave the trojan(s) unrestricted access through your firewall, and I suspect that your Firefox browser hasn't been working correctly because the Norton Smart Firewall or Intrusion Prevention System (IPS) was trying to block an incoming attack from a remote server (or prevent your Firefox browser from connecting to a malicious remote server and sending out stolen information), and was protecting your system exactly as it is designed to do.

Entrepreneer:

...I'm attaching the screenshot (is there a way to get a jpg into this thread without creating a pdf?)....

Hi Entrepreneer:

Your picture doesn't show us what the user interface looks like when you actually start the program but it's still helpful.

If Norton Security Scan is a Windows app rather than an installed program (see the GuidedTech article <here> that explains the difference), go to Start | Settings | Apps and choose Apps & Features from the left pane.  If Norton Security Scan is in your list of Windows apps then select it and see if there is an active Uninstall button (with black text; an inactive button will have grey text) like sample below for the Spotify app on my Win 10 Pro v1909 machine.

Norton Security Scan is often installed during an uninstall of the main Norton Security product. Best not to leave it on your system after reinstalling Norton. It should uninstall from the Windows Settings > Apps.