When accessing backup files on a CIFS (SMB) repository, Veeam Backup and Replication reports either of the following errors:
The specified network name is no longer available. (code 59, 0x8007003B)
An unexpected network error occurred. (code 64, 0x80070040)
Veeam Backup & Replication uses SMB connections for backup repositories, guest processing, and when first adding a Windows server to the Backup Infrastructure. This KB only addresses error messages that occur in the context of a backup file path, such as:
The specified network name is no longer available. Failed to read data from the file [\\10.0.0.81\backups\SQL VM New\SQL VM New2015-09-23T200441.vbk].
Note: If the failure is occurring in a tape job and no UNC path is specified in the error message, please contact Veeam Support.
These error messages are passed directly from Microsoft Windows, and indicate that some unknown problem led to a sudden failure of the connection between the repository gateway (acting as Server Message Block client) and the SMB server (typically a NAS appliance).
There are many possible reasons the SMB connection might fail:
These registry values must be created on the the SMB gateway, which is specified in the repository settings as “Gateway server”. If the gateway is set to “automatic”, add these registry values to all Windows servers managed by Veeam Backup & Replication.
Key: HKLM\SOFTWARE\Veeam\Veeam Backup and Replication\
Value: 10 (Default: 5)