Accessing Windows network shares and UNC paths

Magnus Box can back pull (backup from) and push (backup to) data from Windows network paths and Windows network storage (NAS / SMB / CIFS). This can be added via the web admin dashboard or via the endpoint (see buttons pictured below). The recommended configuration is also listed below, with another screenshot showing an example setup.

Include Paths: "\\LOCAL_IP\SHARE_NAME\" (trailing backslash)

Network Credentials

  • Network Share: "\\LOCAL_IP" (no trailing slash)
  • Password: (insert password to corresponding NAS_ACCOUNT_NAME)
Notes: 1) we recommend using the raw local IP address of the NAS as Magnus Box is sometimes unable to resolve or map a hostname. 2) The "LOCAL_IP\" prefix is not strictly needed, but it has resolved a number of errors in the past, such as the "A specified logon session does not exist. It may already have been terminated" error. Third parties also identify this as a viable solution ( Source 1, Source 2).

Buttons to add NAS credentials

Recommended NAS settings

Installing directly onto NAS (Linux agent and VM option)

If LAN traffic is a concern, there are a few alternative options to capture data stored on a NAS. We currently have a Synology package in open beta, or the Linux agent can be installed directly onto the NAS depending on which flavor of Linux it is running. However, there are some concerns with both setups:
  1. NAS processing power and RAM are usually minimal, which results in slow or erroneous backups
  2. Problems with the "\tmp\" directory allocation (full discussion)
  3. Removal of the "\opt\" directory during major NAS software upgrades - the location of the backup agent (full discussion)

One workaround, which was discovered by a Magnus Box partner, is to create a Windows virtual machine via Synology's Virtual Machine Manager (VMM). Magnus Box can be installed inside the Windows virtual machine and can then map the UNC network path as described above. It may be helpful to add a static IP address for the target NAS to ensure the path is consistently mapped.

Note: while this effectively captures data on the NAS, it may impact performance of the NAS due to the running VM.

Further Troubleshooting

Because Magnus Box runs as a service user, there are some issues with authentication of which is it helpful to be aware.

Mapped network drives

On Windows, each logged-on user session has its own set of mapped network drives. The service user account is unlikely to have any mapped drives. If you see error messages like WARNING Missing: 'Z:\', this is probably the reason. You can work around this by using a UNC path instead.

The Magnus Box desktop application will automatically convert mapped network drives to their UNC path equivalents.


If the UNC share requires authentication, the backup service user account is probably not logged-in to the UNC share. If you see error messages like "WARNING Lstat: CreateFile \\?\UNC\...: Access is denied.", this is probably the reason.

Magnus Box 18.6.5 and later have built-in options for setting Windows network authentication credentials (see above).

For versions of Magnus Box prior to 18.6.5, workarounds are available ranked in order of preference:

  • In Magnus Box, you can work around this issue by adding net use \\HOST\SHARE /user:USERNAME PASSWORD as a "Before" command to the backup job.
    - If you are storing data on a UNC path, you can add this "Before" command on the Storage Vault instead of on the Protected Item. This will ensure it is run for all backup jobs going to that Storage Vault.
  • If you are using Magnus Box to store data on a network device, you may be able to install Magnus Box on the network device. If the network device is a NAS box (e.g. Synology / QNAP), Magnus Box can be installed on Linux x86_64 NAS boxes.
  • You can work around this issue in Magnus Box by changing the Windows Service to use a different user account.
    - This is the Magnus Box (delegate service) service.
    - If you are using Magnus Box on a Windows Server machine that is acting as the Domain Controller, you must choose a domain account.
Did this answer your question? Thanks for the feedback There was a problem submitting your feedback. Please try again later.

Still need help? Contact Us Contact Us