Dear christopher horgli,
Based on your description, if the parent folder has been shared using an Anyone with the link permission, users who access the parent folder through that link may still be able to browse content within it, including subfolders.
To help narrow this down, could you confirm:
- Is this a SharePoint Online document library or OneDrive for Business?
- Can affected users still open files within the subfolder, or can they only see that the folder exists?
- Could you confirm whether the parent folder is shared using an Anyone, People in your organization, or Specific people link?
In the meantime, if the parent folder is shared using an Anyone with the link sharing link, restricting a child folder may not produce the expected result. While unique permissions can be configured on the subfolder, access may still be influenced by sharing links granted at the parent level.
If the subfolder must remain private, the recommended approach is to move the restricted content to a separate folder, document library, or site that is not exposed through the parent folder's anonymous sharing link.
I hope it meets your expectations, if not, please provide some more information as my previous questions so I can support you more effectively.
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