Backing Up to the Network: How to Ensure the Job Runs Reliably via the UNC Path

How do I set up a backup to the network that runs reliably?

Enter the destination in the backup job as \\Server\Backup — not as a drive letter like Z:. Also enter the username and password for the share there. Then the backup will run through at night even when no one is logged on to the computer.

The reason: Windows ties every connection to a share to exactly one user account. Under any other account, the connection is missing. This gives rise to three typical error patterns.

Error pattern 1: The backup grows even though you delete files

Symptom. The destination takes up more and more space. Files deleted long ago are still sitting there.

That's intentional. A backup preserves: what you delete at the source remains at the destination. That saves you when a file disappears by accident or encryption software strikes.

There is a backup type called “synchronization”: it aligns the destination with the source. We advise against it. A synchronization mirrors, it does not back up. Every loss at the source migrates to the destination on the next run — including the one you don't notice until weeks later.

Here's how to free up space and keep the protection:

• Open the “Clean up” window via “Clean up in folders.”
• Select “Clean up deleted files…”.
• You'll see all files that no longer exist at the source. Check off what can really go.

Error pattern 2: The schedule runs, the manual start fails

Symptom. At night the backup runs through to the network storage. If you start the same backup by hand, the run aborts at the destination. Yet you can open the share in Explorer without any problem.

Cause. The nightly backup runs under the account of the background service, the manual start under your own account. Windows ties the connection to the share to only one of the two accounts. Under the other, it's missing — despite administrator rights.

Here's how to solve it.

1. Enter the destination as a UNC path. The UNC path is the direct way of writing a share, for example \\Server\Backup. A drive letter won't do: Windows only knows it as long as you're logged on.

2. Store the credentials in the job.

• Select the topmost backup item.
• Open it via “Edit.”
• On the “Logon” tab, enter the username and password for network access.

With a network storage device (NAS), the credentials alone aren't enough: in the device's web interface, grant the user you entered access to the share folder. New users don't have this access by default.

Then test both paths.

Error pattern 3: Open files are missing from the backup

Symptom. Files from a running business application are missing or appear in the log as locked. The backup runs on the server itself, but the source is the share path \\Server\Daten instead of D:\Daten.

Here's how to solve it.

• Enter the source locally. Unlike the destination, the local path belongs in the job here. Through the share path, Windows can't get to open files.
• Include open files. Enable the option for open files in the job.
• Check the result. Run a backup with the business application open and check the log.

The destination needs the UNC path with credentials — then the backup runs through without a logged-on user. The source needs the local path.