Hi everyone, i need assistance with this recently issue:
Complete internet blocking for all browsers and applications
Detailed description:
Norton 360 has suddenly started blocking internet traffic for ALL my browsers (Firefox, Chrome, Edge) and other applications like Spotify. This happens without any warning or notification - one moment everything works fine, and the next moment all internet connectivity through browsers is completely blocked.
Yesterday (Sept 21): First occurrence around 11:00 AM while working on draw io
Today (Sept 22): Happened again, this time also blocking Spotify traffic
Background: I’ve been using Norton for years without this issue until now
What I’ve Tried
Temporary firewall disable: Doesn’t resolve the issue
Checking program rules: All browsers show as “Allow”
Adding browser exceptions: No effect
Reviewing security history: No obvious triggers or detections
Current Workaround
The ONLY solution that works: Complete Norton uninstallation. As soon as I uninstall Norton, all browsers and applications immediately regain internet access.
Suspected Cause
I suspect this is related to:
Smart Firewall: Possibly being overly aggressive with recent updates
Recent Norton update: This behavior started suddenly after years of normal operation
False positive detection: Norton may be misidentifying normal browser/app traffic as threats
Questions for Community/Support
Has anyone else experienced similar sudden internet blocking?
Is there a way to make Smart Firewall less aggressive without compromising security?
Could a recent Norton update have changed firewall behavior?
Are there specific settings I should check/modify to prevent this?
This is extremely disruptive to daily work, and having to uninstall/reinstall Norton repeatedly is not a sustainable solution. Any guidance would be greatly appreciated.
Product & version number:
OS details: Windows 11 Pro 24H2
What is the error message you are seeing? No any mesage. Just suddenly my browsers and applications are blocked.
I have the same exact problem. It first started like 2-4 days ago. When Windows starts the Internet connection is OK but after a little while all Internet connections stop working: browsers have no Internet access, nslookup command fails and Wi-Fi reconnects in a loop.
I’ve rebooted the computer several times. I also repaired Norton 360 with no luck.
The only solution that worked was uninstalling Norton 360 - the two times I uninstalled Norton 360 then while the uninstall process was still running the Internet connection got restored.
After uninstalling Norton 360 I installed it again but after the install has completed the Internet connection was broken again.
The funny thing is that the Internet gets blocked not immediately after Windows starts but after a few minutes.
Also I tried disabling all the Norton 360 firewall, AV protection, ramsomware protection, Wi-Fi security, Safe Web etc. - literally everything that could be disabled in “Advanced security” list with no success.
I also tried deleting my Wi-Fi network adapter device and driver and reinstalling it with no success
I’m running the latest Norton 360 on Windows 11 Pro with all the current Windows updates installed.
For now I have Norton 360 uninstalled and I’m waiting for a fix before installing it again.
Same problem. I have verified that VPN is OFF, but it still will not allow internet access for many apps, despite selecting “allow forever” in the notification dialog.
has you ask norton support it can be a bug and i think it can be fix in 25.10 ass i got the patch note of curse under nda but i think it is fix in the 25.10 ass it has som major fix in it cant say more if it is not fix before so wait to that update ass i will say one thing and that is the NortonUI bug is fix in the 25.10 and that fixe so many bugs ass it is crazy and it will possible also fix you problem
3 days without connections on many (but not all) WEB sites; it seems that the sites blocked the access (Messages : “ERR_CONNECTION_CLOSED”; “ERR_QUIC_PROTOCOL_ERROR”).
Applications on startup couldn’t start properly : messages “(0xc00000e5).”
After uninstalling the last update of Norton 360 everything came back as formerly.
Hi everyone, i would like to update to all users about my situation:
Product: Norton 360 Issue: Complete internet blocking for all browsers and applications Status: Resolved Monitoring with Microsoft Support Root Cause: Conflicting Windows KB5065426 security update download
Problem Description
Norton 360 was suddenly blocking internet traffic for ALL browsers (Firefox, Chrome, Edge) and other applications like Spotify. This happened without any warning or notification - one moment everything worked fine, and the next moment all internet connectivity through browsers was completely blocked.
Timeline & Symptoms
September 21, 2025: First occurrence around 11:00 AM while working on draw io
September 22, 2025: Happened again, blocking Spotify traffic as well
Previous attempts:FIVE complete uninstall/reinstall cycles - Norton continued to block all traffic after each fresh installation
Background: Using Norton for years without this issue until now
Root Cause Analysis - CRITICAL DISCOVERY
After escalating with Microsoft Support, the root cause was identified:
Norton was blocking or interfering with the download/installation of Windows Security Update KB5065426, creating a conflict between the antivirus and the operating system. This resulted in:
Partial/corrupted update installation causing system instability
SMBv1 protocol conflicts (known vulnerability in KB5065426)
Port 445 blocking affecting all network communications
Cascading failures where Norton interpreted normal system behavior as threats
Microsoft Support Resolution
Microsoft Support took remote control and performed the following steps:
Registry cleanup - Removed corrupted update entries from Windows Registry
Windows Update cache clearing - Deleted failed KB5065426 installation remnants
Manual forced update - Properly installed KB5065426 with clean state
System validation - Verified all components were functioning correctly
Current Status: RESOLVED
Norton 360 reinstalled and functioning normally
No traffic blocking or browser connectivity issues
All applications working (Spotify, draw io, etc.)
System stable with proper KB5065426 installation
IMPORTANT WARNING - Avoid System Restore
Do NOT use Windows System Restore for this issue. System Restore causes additional problems:
Windows Store apps lose registry pointers and become non-functional
Applications require reinstallation or repair to work properly
Widgets and taskbar customizations need to be reconfigured
May worsen the underlying update conflict
Lessons Learned & Recommendations
For Users Experiencing This Issue:
Contact Microsoft Support directly - This requires registry-level intervention
Do not repeatedly uninstall/reinstall Norton - It won’t fix the underlying Windows update problem
Avoid System Restore - It creates more issues than it solves
Document the exact timeline of when issues started
For Norton/Symantec:
Improve compatibility testing with Windows security updates
Better error messaging when blocking system updates
Graceful handling of Windows update processes
Prevention:
Stagger installations - Don’t install Norton immediately after major Windows updates
Monitor Windows Update logs for failures before troubleshooting antivirus
Keep both Windows and Norton updated to latest versions
@JuanBonillaS_S Thank you for the post-back and very detailed solution to the issues you were having. I will bookmark your last post for easy finding to refer other to indeed.
Unfortunately your solution will not work in my case as I had already KB5065426 installed successfully on 10.09.2025 (2 weeks ago) but issues started like 2-4 days ago. I am not experiencing any system instability.
I checked the system files integrity using DISM and sfc and everything is fine.
SĂĄ vente til 25.10 da jeg er 99% sikker pĂĄ at den er fix der NortonUI fejlen retter sĂĄ mange fejl at det er vanvittig minimum 7 vil jeg tror mĂĄske mere lige fra major til miner da jeg ved minimum 2 fejl den retter men der er bare 2 der er mange flere under den da jeg tror ogsĂĄ andre er ramt af det men det er jo bare en teori de 2 er bare dem jeg er sikker pĂĄ ikke andet
I also have this issue, started on Friday 9/19/2025, everything was working and then boom, all browsers had no internet. Other programs like outlook had internet, windows showed I was online, others were online on my network. It has happened multiple times a day since, some times a few minutes after reboot or hours. Tried turning off all the Norton items it allows, firewall, AV protection, essentially all items I can turn off, even went through every option within Norton to turn off everything. The only thing that works was to reboot.
Then the clock starts ticking again, until i would suddenly loose internet again.
I finally had enough, so I uninstalled Norton, and my browsers started working as soon as the un-installation of Norton was finished. No reboot.
I wasted hours looking online researching for a solution, the only solution I found was to uninstall Norton.
I should note as per the user above, 2025-09 Cumulative Update for Windows 11 Version 24H2 for x64-based Systems (KB5065426) (26100.6584) was installed 9/12/2025 which was long before this issue started.
i has info max 5-7days and they has a fix says Norton that is there plan plus the stabelety bug is also plan in that hotfix plus there was a firewall bug also plan in that hotfix
I’m glad to have found this thread as I thought I’ve been going crazy. I’ve had the same problem on multiple Windows 11 machines that have never used the VPN function. Problems began on 9/19. Only thing that fixes it is a complete and total uninstall. (Repair installs and complete uninstall with settings deleted followed by a reinstall all had the same problems immediately reoccur).
I’ve used Norton since the Peter Norton days. I’m cancelling my 360 Premium subscription.
norton sender extreme mange hotfix ud til norton 360 de næste uger så tag det rolig alt er nok rettet onsdag næste uge plus det der ikke er rattet der bliver rattet i norton 360 25.10 som det ser ud nu
This update appears to interfere with Norton 360’s network protection features. While reinstalling Norton may temporarily restore access, it’s not a permanent fix. Norton has acknowledged the issue and is working on a resolution, which may take 24–48 hours. In the meantime, some users have found relief by uninstalling the KB5065426 update or using Microsoft’s “Show or Hide Updates” tool to prevent it from reinstalling
We recommend keeping an eye on Norton’s official support page for updates here, and feel free to reach out if you need help with temporary workarounds.
The good news is that Norton is actively working on multiple bug fixes, and updates are expected to roll out soon. While we don’t have an exact release time, Norton typically pushes fixes through automatic updates. So we recommend:
Norton 360 reinstalled and functioning normally
IMPORTANT WARNING - Avoid System Restore