Guest OS File Restore Fails on Self-Referencing Junction Points
Challenge
Using Guest OS File Restore to restore a folder containing a junction point that redirects back to the initial folder fails with the error:
Win32 error:The name of the file cannot be resolved by the system. Code: 1921
For example, attempting to restore a user's AppData folder the restore will fail with:
Failed to restore "\\?\C:\Users\backupsvc_RESTORED_20241010_135355\AppData\Local\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data\Application Data": Failed to start folder iteration. Win32 error:The name of the file cannot be resolved by the system. Code: 1921
Cause
This occurs because Guest OS File Restore does not restore junction points; it attempts to restore the actual content of the junction point.
As documented in the Veeam Backup & Replication User Guide:
Veeam Backup & Replication restores junction points as folders with the content they refer to. If a junction point refers to the folder in which it lies or to the parent folder, restore will fail.
The Windows OS (desktop and server) includes such a junction point that will cause the error shown in the example. Within the folder C:\Users\<user>\AppData\Local is a junction point named 'Application Data', which is a junction back to C:\Users\<user>\AppData\Local, creating a self-referential loop.
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Solution
More Information
The following two self-referential junction points are known to exist in Windows desktop and server operating systems:
- [C:\ProgramData\Application Data] -> [C:\ProgramData]
- [C:\Users\<user>\AppData\Local\Application Data] -> [C:\Users\<user>\AppData\Local]
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