Offline Files (CSC) – Sync Center shows no partnership for specific users despite GPO-configured Folder Redirection

Question

Hi everyone,

we are experiencing a persistent Offline Files synchronization issue in our environment and are looking for guidance.

Environment

• Windows 10/11 Enterprise (physical workstations)
• Domain-joined, GPO-managed
• User home drive (P:) mapped via DFS Namespace
• Offline Files / CSC enabled via GPO
• Folder Redirection configured via Group Policy (no AssignedOfflineFolders registry key present – partnerships are GPO-driven)

Problem The issue is user-specific, not device-specific – the same users experience it across different machines. In Sync Center (mobsync.exe), affected users show no partnership at all for their home drive, even though Offline Files is enabled and other users on the same device sync correctly.

Known trigger scenarios include: profile migrations, manual profile deletions, CSC cache resets, and switching between physical client and VDI sessions. Resetting the CSC cache does not resolve the issue permanently – the partnership does not re-establish itself reliably after reboot.

What we have already checked

• HKLM\SYSTEM\CurrentControlSet\Services\CSC\Parameters → Start = 1, CachingEnabled correct
• HKCU\Software\Microsoft\Windows\CurrentVersion\NetCache → not present (rules out user-level override)
• AssignedOfflineFolders → not present (partnerships are fully GPO-driven)
• Event Log Microsoft-Windows-OfflineFiles/Operational → no critical errors for affected users
• OneDrive KFM → ruled out as conflicting factor
• DFS Namespace in use → suspected as potential silent failure point
• GPO exports and Folder Redirection configuration currently under review

Question What can cause Offline Files partnerships to silently not establish for specific users in a GPO/DFS environment, even after cache resets? Are there known interactions between DFS Namespace and CSC that can prevent partnership creation without logging errors?

Any hints on further diagnostic steps or known fixes are appreciated. Thanks in advance.Hi everyone,

we are experiencing a persistent Offline Files synchronization issue in our environment and are looking for guidance.

Environment

• Windows 10/11 Enterprise (physical workstations)
• Domain-joined, GPO-managed
• User home drive (P:) mapped via DFS Namespace
• Offline Files / CSC enabled via GPO
• Folder Redirection configured via Group Policy (no AssignedOfflineFolders registry key present – partnerships are GPO-driven)

Problem The issue is user-specific, not device-specific – the same users experience it across different machines. In Sync Center (mobsync.exe), affected users show no partnership at all for their home drive, even though Offline Files is enabled and other users on the same device sync correctly.

Known trigger scenarios include: profile migrations, manual profile deletions, CSC cache resets, and switching between physical client and VDI sessions. Resetting the CSC cache does not resolve the issue permanently – the partnership does not re-establish itself reliably after reboot.

What we have already checked

• HKLM\SYSTEM\CurrentControlSet\Services\CSC\Parameters → Start = 1, CachingEnabled correct
• HKCU\Software\Microsoft\Windows\CurrentVersion\NetCache → not present (rules out user-level override)
• AssignedOfflineFolders → not present (partnerships are fully GPO-driven)
• Event Log Microsoft-Windows-OfflineFiles/Operational → no critical errors for affected users
• OneDrive KFM → ruled out as conflicting factor
• DFS Namespace in use → suspected as potential silent failure point
• GPO exports and Folder Redirection configuration currently under review

Question What can cause Offline Files partnerships to silently not establish for specific users in a GPO/DFS environment, even after cache resets? Are there known interactions between DFS Namespace and CSC that can prevent partnership creation without logging errors?

Any hints on further diagnostic steps or known fixes are appreciated. Thanks in advance.

Answer 1

Hallo

Wurde dein Problem schon gelöst? Falls ja, erwägen Sie bitte, die Antwort zu akzeptieren, da sie auch anderen mit demselben Problem hilft, davon zu profitieren. Danke :)

VPHAN

Answer 2

Hallo Mike,

Um diesen persistenten Synchronisationsfehler bei Offline-Dateien zu beheben, muss Netzwerkpfadabweichungen korrigiert und lokalisierte Profilbeschädigung behoben werden. Die Client-Side Caching-Engine verlangt absolute Pfad-Uniformität, was bedeutet, dass jede Diskrepanz zwischen einem in Ihrer Folder Redirection Group Policy verwendeten Fully Qualified Domain Name und einem NetBIOS-Namen, der im Active Directory Home Folder-Attribut eines Benutzers definiert ist, dazu führt, dass die Partnerschaftsgründung stillschweigend abgebrochen wird. Stellen Sie sicher, dass diese Active Directory- und Gruppenrichtlinienpfade identisch sind, um zu verhindern, dass die Synchronisations-Engine sie als zwei getrennte Orte behandelt.

Die Standardmethode, den Offline-Dateicache zurückzusetzen, indem der FormatDatabase-Wert im Registrierungsschlüssel HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\CSC\Parameters erstellt wird, löscht nur die systemweite Datenbank. Diese Aktion lässt die beschädigte, benutzerspezifische Konfiguration in ihrem Migrationsprofil erhalten. Du musst den Sync Center-Ordner manuell löschen, der sich im versteckten C:\Users[Benutzername]\AppData\Local\Microsoft-Verzeichnis des betroffenen Nutzers befindet, während er vollständig abgemeldet ist, um beim nächsten Login die Erstellung eines sauberen Synchronisationsprofils zu erzwingen. Gleichzeitig wird der lokale Distributed File System-Cache auf dem Client-Rechner mit Standard-Kommandozeilen-Tools gelöscht, um veraltete Routing-Referrals zu vermeiden, die die Verbindung zum Hostserver stören könnten.

Ich hoffe, diese Antwort hat Ihnen nützliche Informationen gebracht. Falls ja, klicken Sie bitte auf "Antwort akzeptieren". Sollten Sie Fragen haben, hinterlassen Sie gerne einen Kommentar.

VPHAN