Shane
August 23, 2026, 1:28am
1
I’m getting a message saying “Backup has failed”. Security History says the error code is 536873134. How can I find out which files didn’t back up, or what this error code means?
Shane
Norton 360 Premium 26.8.11125 (build 26.8.11125.0)
bjm
August 23, 2026, 1:41am
2
Hello @Shane
Error Code 536873134
Locked Files: A file included in the backup set was open or actively in use by another Windows 11 background task.Long Character Paths: Windows 11 file paths that exceed 256 characters can cause the backup engine to hang and timeout.Permission Blocks: The app lacked local system permissions to read specific protected user folders.Corrupted Local Engine: A localized bug within your specific build’s cached files
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Here’s step-by-step summary for finding your files and fixing error 536873134 in the Norton v26 interface on Windows 11:
Find Which Files Failed
Open Norton 360 .
Click Security on the left menu.
Click the Security History tile.
Change the drop-down filter from “Recent History” to Cloud Backup .
Double-click the Failed entry to see the specific file paths.
Run Repair Norton
Click the Settings gear icon in the bottom-left corner.
Select Troubleshooting .
Click Repair Norton (this fixes the engine without wiping your settings).
Warning: Do not click “Reset to Default,” as this resets Cloud Backup
Clear the Communication Error
Sign Out / Sign In : Click your profile icon at the top right, select Sign Out , restart your PC, and Sign In again to reset the cloud handshake.Run as Admin : Right-click your desktop Norton icon and choose Run as Administrator to bypass Windows 11 file permission blocks.
Let me know if the Repair Norton tool successfully completed, or if the backup continues to fail on the exact same files.
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Understanding Error 536873134 in v26
In version 26, error 536873134 points to a file access or stream interruption during the upload phase. This typically occurs when:
A file included in the backup is actively open or locked by another process (e.g., an open document, database, or system log).
A file path exceeds standard character limits or has restricted read permissions.
The upload stream to Norton Cloud drops mid-transfer.
Finding Skipped / Failed Files in v26.8
Because Norton v26 removed the detailed per-file breakdown from the primary error notification, use these methods within the redesigned interface to locate what failed:
Method 1: Check File Status Icons in File Explorer
Open Norton 360 v26 .
Click the Settings (gear icon) in the bottom-left corner.
Select Backup (or Cloud Backup ).
Ensure Backup status icons is toggled ON .
Open Windows File Explorer and look at your source folders (Documents, Pictures, etc.).
Look for files marked with a Red Warning/X (failed) versus a Green Checkmark (backed up).
Method 2: Inspect Security History Logs
Open Norton 360 v26 .
Click Settings (gear icon) $\rightarrow$ Security $\rightarrow$ History .
In the top category filter, select Cloud Backup .
Click on the log entry showing error 536873134. The details pane below will display the specific target path or folder where the backup routine stalled.
Method 3: Check the Restore Interface
In Norton 360, go to Cloud Backup on the main dashboard.
Click Restore .
Select your backup set and click Browse Files .
Expand the tree to see which of your local files have a current cloud copy and which were skipped.
Recommended Fixes for v26
Close Applications: Close active software (Word, Excel, browser sessions) before running the backup so no target files are locked.Exclude Temp Folders: In Backup Settings, check your target paths to ensure dynamic temporary folders (like AppData\Local\Temp) aren’t selected.Test a Small Set: Create a temporary test backup set with just one folder. If it completes without 536873134, the issue is isolated to a specific locked file in your main set.
AI sourced content may make mistakes
bjm
August 23, 2026, 2:09am
3
Hello @Shane
Have you tried Repair Norton
Have you reviewed: Security History → Cloud Backup → Advanced details here … review → # files failed to back up
for example: 7 files failed to back up
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Get started using Norton Cloud Backup Restore pictures, music, or other important files from Norton backup sets Learn more about Cloud Backup Norton Cloud Backup timestamp is incorrectly displayed in your Norton 360 app
bjm
August 23, 2026, 2:20am
4
If Norton cloud backup fails, check for insufficient cloud storage, ensure your Norton software is up to date, verify your backup settings, delete and recreate backup sets, and try running the backup again after a short period. You may also find a red cross (x) icon next to the backup status, which indicates a complete failure and requires further troubleshooting to resolve.
Possible Causes for Norton Cloud Backup Failure
Insufficient Storage Space :
If you have used all your available cloud storage, new files will not be backed up.
An outdated version of Norton 360 can lead to backup issues.
Incorrect backup settings or an issue with the backup location can cause failures.
A corrupted backup set may prevent future backups from completing successfully.
Troubleshooting Steps
Check Backup Status : Look for the status icon next to your backup in the Norton app. A red cross (x) indicates a complete failure.Check Cloud Storage : Verify your current cloud storage usage.Update Norton Software : Make sure you are running the latest version of Norton 360.Review Backup Settings :
Go to the Cloud Backup tile in your Norton product.
Select Advanced details or the Settings tab to review your backup set and settings.
Consider turning off “Back up common file types only” if it is set to on and you have files it is excluding.
Delete and Recreate Backup Sets :
Delete any backup sets you no longer need to free up space.
Create a new backup set with the correct settings.
Exclude Problematic Folders : If a specific folder is causing issues, try excluding it from your backup.Run Backup Again : After making changes, try running the backup again.
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If Norton Cloud Backup sync fails, you should first check for insufficient online storage, slow internet, or issues with your Norton 360 program. Try restarting your computer and router, then use the Cloud Backup window to review your backup settings and add any files to the backup set, or reset your backup set to default. If these steps don’t work, you may need to exclude the "System Volume Information folder from your backup or use the Norton Remove and Reinstall tool to fix corrupted files.
Check for Basic Issues
Internet connection:Ensure your internet connection is stable and not unusually slow.
Storage space:Check if you have enough cloud storage space or if you need to upgrade your Norton plan.
Norton program:Make sure your Norton 360 program is up-to-date and restart your computer.
Review Backup Settings in Norton 360
Open Norton 360 and go to the Security dashboard.
Select the Cloud Backup tile.
Click Manage or Manage Files next to the backup set you want to update.
Go to the Files tab and click Add to add any files or folders you want to include in the backup.
Check the Settings tab for the option to “Back up common file types only” and turn it Off if it’s enabled, as this might be preventing files from syncing.
Go to Excluded files → Manage and check if you’ve accidentally excluded the files you need to back up.
Troubleshoot the Backup Sync Failure
Review Security History: Look for the specific backup failure message in your Security History to understand the cause.Reset Backup Set: If you see the “Failed to sync backups” message, try deleting the specific backup set that is failing and then create a new one.Exclude Specific Folder: If the backup is trying to back up the “System Volume Information” folder, exclude it from your backup.
AI sourced content may make mistakes
bjm
August 27, 2026, 2:19pm
5
Hello @Shane
