Separate a missing library from a missing film
If one person cannot see a newly added library while the administrator can, inspect library access before rescanning every file. A whole library absent for one account is a different observation from a single item being incorrectly identified inside an accessible library.
Read the documented inheritance rule
Jellyfin’s user-management guide says Enable access to all libraries includes the broad arrangement. When that option is disabled and libraries are selected individually, a newly added library is not automatically accessible to that user. The administrator can later change the selection. The new library can therefore be healthy and populated while remaining outside one user’s permitted set.
Apply the narrow access change that was intended
For example, an administrator adding a household home-video library can decide which local users should receive it, then inspect those users’ explicit library selections. There is no need to enable access to every unrelated library merely to reveal the new one. Save the intended selection and check the client signed in as that user. If the library is then visible but one file remains absent, investigate that item separately. Keep the server, user context and missing library name with a support report rather than saying the application lost the entire collection. Do not share the administrator password as a shortcut to ordinary viewing access.
Questions, answered
Will an explicitly restricted user inherit every library added later?
Jellyfin says a user without all-library access will not automatically receive new libraries.