Access Denied Writing Files to Media Folders: Emby Server on Windows w/ Mapped Network Drive - Running as User

[AriZoNaiCe 2]

As the title suggests, I am running Emby Server on Windows with a mapped network drive (Z:) for media.  Those shares exist on a QNAP NAS with a matching user/password pair from the Windows user, which is what has been used to map the drives.

Emby is updating my metadata for a new library incredibly slowly (36h so far for 2,400 items) , so I started digging into the logs to see what might be the cause.  I see that it is struggling with all writes to the shares.  Below is a relevant log entry (username and title obfuscated).

I have read a ton of entries related to when running Emby as a service.  That makes perfect sense, since shared drives exist in the context of a user and are not accessible without an interactive logon.  But since Emby is running as the user, using the standard tray icon configuration, and the user has read/write on the shares (tested via Windows Explorer and CLI), I'm not sure what's going on.  My first thought is that Emby is spawning a process in the background to handle these writes and that process is not running as the user...or it's running into something related to multi-hop or implicit tokens when trying to write to the share.

The related ffprobe logs seem to have no issue reading from the media folders, and the http calls all appear to be successful.

Any help would be greatly appreciated.

2025-01-08 12:00:42.327 Error App: Error creating thumbnails for Z:\Movies\Movie (0000)\Movie (0000).mkv
    *** Error Report ***
    Version: 4.8.10.0
    Command line: C:\Users\user01\AppData\Roaming\Emby-Server\system\EmbyServer.dll
    Operating system: Microsoft Windows 10.0.19045
    Framework: .NET 6.0.33
    OS/Process: x64/x64
    Runtime: C:/Users/user01/AppData/Roaming/Emby-Server/system/System.Private.CoreLib.dll
    Processor count: 8
    Data path: C:\Users\user01\AppData\Roaming\Emby-Server\programdata
    Application path: C:\Users\user01\AppData\Roaming\Emby-Server\system
    System.UnauthorizedAccessException: System.UnauthorizedAccessException: Access to the path 'Z:\Movies\Movie (0000)\Movie (0000)-320-10.bif' is denied.
       at System.IO.FileSystem.CopyFile(String sourceFullPath, String destFullPath, Boolean overwrite)
       at Emby.Providers.MediaInfo.ThumbnailGenerator.CreateThumbnailSet(Video item, MediaStream videoStream, LibraryOptions libraryOptions, Int32 width, CancellationToken cancellationToken)
       at Emby.Providers.MediaInfo.ThumbnailGenerator.CreateThumbnailSets(Video item, MediaStream videoStream, LibraryOptions libraryOptions, CancellationToken cancellationToken)
       at Emby.Providers.MediaInfo.ThumbnailGenerator.RefreshThumbnailImages(Video item, MediaStream videoStream, LibraryOptions libraryOptions, IDirectoryService directoryService, List`1 chapters, Boolean extractImages, Boolean saveChapters, CancellationToken cancellationToken)
    Source: System.Private.CoreLib
    TargetSite: Void CopyFile(System.String, System.String, Boolean)

Thank you.

[Abobader 3464]

Hello AriZoNaiCe,

** This is an auto reply **

Please wait for someone from staff support or our members to reply to you.

It's recommended to provide more info, as it explain in this thread:

Thank you.

Emby Team

[Luke 42078]

HI, one thing you could try is setting up the library using the original network location, rather than a mapped drive.

Keep in mind on windows, all of this is handled by the OS. You don't enter the username and password to the network share into Emby because Windows handles that part for us.

[AriZoNaiCe 2]

Thank you for the quick reply!  I should totally have included that information -- I actually had it configured that way first and had the same errors.  I changed it thinking maybe it would be better as a mapped drive.   Are we sure there are no 3rd-party processes being spawned that could potentially be as a different user?

[Luke 42078]

The mapped drive only adds an extra layer, which in the end just means another possible point of failure.

Quote

Are we sure there are no 3rd-party processes being spawned that could potentially be as a different user?

There are, but not for the example above.

[AriZoNaiCe 2]

1 minute ago, Luke said:

The mapped drive only adds an extra layer, which in the end just means another possible point of failure.

There are, but not for the example above.

Understood -- I'll keep hunting.  Can't thank you enough for the quick replies!

[Luke 42078]

Please let us know what you find. Thanks !