Intermittent backup failures to network share

Question

Scheduled backups to a network share sometimes fail with “network path not found,” even though the share is accessible. This may point to SMB session timeouts or credential caching problems with the backup service account ?

Answer 1

Hello @Adin Mohhamed

Based on your description, SMB session timeouts or authentication issues are certainly possible, but there are a few other areas worth investigating before concluding it's a credential caching problem.

I would recommend checking the following:

• Verify whether the backup service is running under a dedicated service account and that the account has continuous access to the network share.
• Review the Windows Event Viewer on both the backup server and the file server for SMB Client/SMB Server, LanmanWorkstation, and backup application events that coincide with the failures.
• Confirm that DNS resolution and network connectivity remain stable during the backup window (for example, intermittent network interruptions can produce "network path not found" errors).
• Check for SMB session disconnects, idle timeouts, or Group Policy settings that may affect long-running network sessions.
• If the backup target is a NAS device, verify its SMB protocol version and whether it has connection timeout or session limit settings.

You could also test accessing the share using the same service account that the backup job runs under to confirm there are no permission or authentication issues.

If the failures occur at regular intervals, correlating the timestamps with Event Viewer logs and the backup application's logs can often reveal whether the issue is caused by network connectivity, SMB session termination, or authentication renewal.

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