Norton 360 Premium is blocking/impeding access to DropBox files stored in the cloud. Subsequently stops internet access and brings my system to a halt.
**Detailed description:
NORMALLY:** Files stored on Dropbox with links stored on MacBook, are usually seamless to access and work with.
Press spacebar on a file, and macOS Preview downloads the file and shows a preview of its contents, all in <1s.
Double-click on a file and macOS downloads the file and opens it with the registered app.
**SINCE MONDAY (**roughly, Nov 10):
Hitting spacebar for a Preview results in spinning beachball for up to 5 mins. Sometimes a Preview then appears, sometimes not. Feels like the function is timing out.
Double-click to download and open a file: the file freezes mid-download for up to 5 mins. Sometimes downloads, more often times out.
Right-click manual download: file freezes mid-download for up to 5 mins. Sometimes downloads, more often times out.
IF I do anything else when this is happening, all subsequent Internet access is halted. Apps won’t open, webpages won’t open. System hangs for up to 10 mins THEN everything happens simultaneously like it had all been frozen or hanging and then everything times out and releases.
WHAT HAVE I DONE?
Updated macOS to current version
Removed and reinstalled Norton 350 (about 10 times); cleaned system between installations
Ran Update for app and virus definitions
Disabled/enabled Smart Firewall
Added DropBox exception to Intrusion Prevention
Added DropBox exception to Safe Web filtering
Disabled/enabled Download Intelligence
Added a Allow rule for DropBox in Smart Firewall
Added DropBox.com to EVERY Exclusion field I could find
HOW DO I KNOW IT’S NORTON?
As soon as I remove Norton, my Mac behaves as it should.
Product & version number:
Norton 360 Premium for Mac. No idea where version number is found.
OS details:
macOS 26.1 (Tahoe) updated yesterday
MacBook Pro M4 MAX 36Gb
2.5Gb LAN
What is the error message you are seeing?
See above
AI Mode
To resolve issues with Norton 360 for Mac blocking Dropbox and internet access, you need to adjust specific firewall and security settings within the Norton application to add exceptions for Dropbox.
Step 1: Allow Dropbox Access in Norton Firewall Settings
The firewall is likely preventing the Dropbox application from connecting to the internet and cloud servers.
Open Norton 360 on your Mac.
In the main window, click Advanced or Settings (usually in the menu bar).
Navigate to Firewall. You might need to click the lock icon in the bottom-left corner and enter your administrator password to make changes.
Go to the Program Control (or Application Blocking) tab.
Look for Dropbox in the list of applications.
Ensure the access setting for Dropbox is set to Allow (usually shown as green dots or “Allow Access”).
If Dropbox is not listed, you can often add it manually using a [+] button or an Add Application option. Browse to your Applications folder, select the Dropbox.app file, and grant it full access.
Save your changes.
Step 2: Add Dropbox to Antivirus Exclusions
Norton’s real-time scanning might be interfering with Dropbox’s syncing process, causing system slowdowns and file access issues.
Open Norton 360 and go to Settings or Preferences.
Navigate to the Antivirus section.
Look for a tab or option labeled Scans and Risks or Exclusions.
Find an option like Items to Exclude from Scans or Scan Exclusions.
Add the main Dropbox application (/Applications/Dropbox.app) and your local Dropbox sync folder (e.g., /Users/YourUsername/Dropbox) to the exclusion list.
Save the settings.
Step 3: Check and Disable Conflicting Features (Temporarily)
Certain network-monitoring features may cause conflicts with Dropbox’s network protocols.
Disable Connection Blocking/Intrusion Prevention:
Go back to Settings > Firewall.
Temporarily disable “Connection Blocking” or “Vulnerability Protection” to see if the issue is resolved. If it is, you may need more advanced configuration in these settings.
Check VPN Settings:
If you are using the built-in Secure VPN feature, open Settings > VPN.
Temporarily turn off the VPN to check if network access is restored. If the issue stops when the VPN is off, you might need to find a way to exempt the Dropbox service from the VPN connection.
Step 4: Reinstall the Dropbox Application
If the conflict persists after configuring the settings, a fresh installation of Dropbox may clear the issue.
Uninstall the Dropbox app from your Applications folder.
Restart your Mac.
Download the latest version from the official Dropbox website and reinstall it.
Step 5: Contact Support
If the problem remains unresolved, specific configuration advice may be needed from the software providers.
Contact Norton Customer Support for Mac-specific guidance.
You can also find community help and solutions on the Dropbox Community forum.