Datto Endpoint Backup v2 - Backups failing due to recursive directories and path length issues

Description

Resolution for users having backup failures in Datto Endpoint Backup v2.  Suggested helpdesk user Level 2. Estimated time to resolution: 60 to 90 minutes, depending on data volume and cleanup effort.

Issue synopsis

Backups using Datto Endpoint Backup v2 not making progress.  Investigation showed that the root cause was problematic file system structures, including recursive directories and file paths that were too long for the backup agent to process.

Resolution summary

The issue was resolved by identifying and sanitizing problematic directories, purging, or excluding these directories. After the cleanup, the backup agent services were restarted and the backup completed successfully.

Step by step resolution instructions

1. Confirm product and environment
   • Verify the endpoint is running a supported version of Windows.
   • Confirm Datto Endpoint Backup v2 version, verify using the latest agent.
2. Collect agent logs
   • Increase log level to TRACE.
     • Full file names and paths may not be present at the default log level.
   • Logs are located in C:\Windows\System32\config\systemprofile\AppData\Local\Datto Backup Agent\
   • Gather relevant backup logs from the endpoint.
3. Identify problematic directories
   • Focus on user profile locations:
     • Look for:
       • Repeated folders nested inside each other.
       • Recursive directory structures where a folder contains a link or junction back to a parent path.
       • Paths that appear excessively long or deeply nested.
       • Issue often presents when robocopy is used to copy user profiles between endpoints.
4. Plan directory sanitization and exclusions
   • Verify which directories are safe to clean up or exclude from backup.
   • Confirm that no critical production data is stored in the problematic recursive folders.
5. Restart backup agent services
   • Restart the Datto Endpoint Backup v2 agent service on the endpoint after cleanup.
   • Verify that the service starts without errors.
6. Confirm resolution
   • Review the backup job status and log
   • Confirm that the backup finished successfully and that no new errors are present in the log
   • Decrease log level back to default

Warnings

• Recursive directories and long file paths cause backup failures and should be carefully reviewed before deletion.
• File paths that are too long may prevent the backup agent from processing files and can lead to repeated job failures.
• Improper deletion of system or application data may impact user profiles or application behavior.

Useful links

• https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=registry

Additional troubleshooting tips

• If similar errors persist after cleanup, check logs for additional long file paths.
• Check for symbolic links or junction points that may create hidden recursion in user profile directories.
• Consider running a file system scan to detect path length issues or corrupted directories.