Work Folders sync failing with sync relationship error

David Brown 0 Reputation points
2026-07-28T17:27:41.7033333+00:00

When a subset of users tries to sync Work Folders, they cannot access the sync options because it fails with "sync relationship could not be established."

What's the certificate / AD FS dependency check for Work Folders?

Windows for business | Windows Server | Directory services | Certificates and public key infrastructure (PKI)
0 comments

1 answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. Allan Solomon Mejia 2,595 Reputation points
    2026-07-28T20:02:17.2866667+00:00

    Hi @David Brown

    The "Sync relationship could not be established" error typically indicates that the client cannot successfully complete the registration process with the Work Folders server. Since only a subset of users is affected, it's worth comparing those users against ones that are working to identify any differences in certificates, authentication, or user configuration.

    Here are the main dependencies to verify:

    • SSL certificate – Ensure the Work Folders endpoint is using a valid server certificate that the affected clients trust. The certificate's subject/SAN must match the Work Folders URL, and the certificate must not be expired or revoked.
    • DNS and connectivity – Verify affected clients can resolve and reach the Work Folders endpoint over HTTPS (TCP 443).
    • Authentication – If you're using AD FS, confirm the affected users can successfully authenticate through AD FS and that the relying party trust and claim rules are functioning correctly. If Microsoft Entra ID is used instead, verify the sign-in process succeeds.
    • User provisioning – Ensure the affected users have been configured for Work Folders on the server and have the appropriate NTFS and share permissions.
    • Certificates on the client – If your deployment requires client certificates, verify the required certificate is present in the user's certificate store and has not expired.
    • Event logs – Review the Applications and Services Logs > Microsoft > Windows > WorkFolders logs on both the client and server, as well as the AD FS event logs (if applicable). These often provide the specific reason why the sync relationship failed.

    A few questions that may help narrow it down:

    • Are you using AD FS or Microsoft Entra ID for authentication?
    • Does the issue affect only newly onboarded users, or also existing users?
    • Have there been any recent changes to certificates, AD FS, or the Work Folders server configuration?

    Please "Accept the Answer" if this information helped you. This will help us and others in the community as well.

    Was this answer helpful?

    0 comments

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.