error unmarshaling YAML data: [19:21] mapping was used where sequence is expected

[Cetheus]

Hi everyone,
I'm getting really pissed atm.

Yesterday I ran an Update of my Docker-Container and since then, it won't start up.

The Log-File shows the following error:

2026/03/08 10:08:15 [ERROR] unable to load config, waiting 5 seconds before exiting...
2026/03/08 10:08:20 [FATAL] error unmarshaling YAML data: [19:21] mapping was used where sequence is expected
  16 |       defaultEnabled: false
  17 |       defaultUserScope: /
  18 |       rules:
> 19 |         ignoreHidden: true
                           ^
  20 |         ignoreZeroSizeFolders: false
  21 |     name: pbroot
  22 |     path: ./data/work

I validated that the yaml is working.
I tried the full example file,
I tried my old config file,
I tried a new config file copied from the example and migrated my old config file.
But the Error consists.

This is my config.yaml: (I removed the URL for reasons)

server:
  port: 80                                # port to listen on
  baseURL: "/"                            # base URL for the server, the subpath that the server is running on.
  logging:
    - levels: "info|warning|error"                          # separated list of log levels to enable. (eg. "info|warning|error|debug")
  sources:                                #  validate:required,dive
    - path: "./data/work"  # file system path. (Can be relative)  validate:required
      name: "pbroot"                 # display name
      config:
        rules:                            # list of item rules to apply to specific paths
            ignoreHidden: true           # Excludes only hidden files and folders
            ignoreZeroSizeFolders: false  # Excludes only folders with 0 size
        defaultUserScope: "/"             # defaults to root of index "/" should match folders under path
        defaultEnabled: false              # should be added as a default source for new users?
        createUserDir: false              # create a user directory for each user under defaultUserScope + username
frontend:
  name: "Filebrowser"             # display name
  disableDefaultLinks: true              # disable default links in the sidebar
  externalLinks:
    - text: "Testinstanz"                 # the text to display on the link  validate:required
      title: "Just testing"                  # the title to display on hover
      url: "https://<myurl>" # the url to link to  validate:required
userDefaults:
  darkMode: true                          # should dark mode be enabled
  locale: "de"                            # language to use: eg. de, en, or fr
  singleClick: false                      # open directory on single click, also enables middle click to open in new tab
  disableSettings: false                  # disable the user from viewing the settings page
  preview:
    image: false                           # show thumbnails for image files
    video: false                           # show thumbnails for video files
    audio: true                           # show thumbnails for audio files
    motionVideoPreview: false              # show multiple frames for videos in thumbnail preview when hovering
    office: false                          # show thumbnails for office files
    popup: false                           # show larger popup preview when hovering over thumbnail
    autoplayMedia: false                   # autoplay media files in preview
    defaultMediaPlayer: false             # disable the styled feature-rich media player for browser default
    folder: true                          # show thumbnails for folders that have previewable contents
    models: false                          # show live thumbnails for 3D models files
  permissions:
    api: false                            # allow api access
    admin: false                          # allow admin access
    modify: false                         # allow modifying files
    share: false                          # allow sharing files
    realtime: false                       # allow realtime updates
    delete: true                         # allow deleting files
    create: true                         # allow creating or uploading files
    download: true                        # allow downloading files
  loginMethod: "password"                 # login method to use: eg. password, proxy, oidc
  deleteWithoutConfirming: false          # delete files without confirmation
  fileLoading:                            # upload and download settings
    maxConcurrentUpload: 10
    uploadChunkSizeMb: 10
    clearAll: false
    downloadChunkSizeMb: 0

Can someone please help me, why I'm getting this Error?
I don't get, why I get the Error in line 19, even if in my config file my line 19 is " externalLinks:"

And finally my docker-compose:

services:
  filebrowser:
    environment:
      FILEBROWSER_CONFIG: "/home/filebrowser/data/config.yaml" 
    volumes:
      - /home/docker/filebrowser:/home/filebrowser/data # Never mount root "/" directory to docker, always choose a sub-folder with your data.
    ports:
      - '23999:80' # the left 80 is the port **you will use** to access. The right 80 is the container port that **must match the config.yaml**
    image: gtstef/filebrowser
    healthcheck:
      test: ["CMD", "curl", "-f", "http://localhost:80/health"] # port should match the internal port 8080 
      interval: 30s
      timeout: 3s
      start_period: 10s
      retries: 3
    restart: unless-stopped

Thank you in advance for any help given.
Greetings Cetheus

[gtsteffaniak]

There was a change to the rules structure where the root configs are deprecated -- I thought it was backwards compatible though so it wouldn't break.

This started in the v1.2.0 release

The new style is to use global rules, which should resolve your problem for now. But, this was meant to be a graceful non-breaking change. So let me see if I can fix this for everyone else that wasn't aware.

[Cetheus]

Going through the Config I discovered some little Things.

preview:
  audio: true
  model: false

Both are throwing an Error:

2026/03/09 09:22:24 [FATAL] error unmarshaling YAML data: [51:5] unknown field "models"
  48 |     defaultMediaPlayer: false
  49 |     folder: true
  50 |     image: false
> 51 |     models: false
�
           ^
  52 |     motionVideoPreview: false
  53 |     office: false
  54 |     popup: false
  55 |     
2026/03/09 09:22:26 [DEBUG] Default SQLite driver initialized
2026/03/09 09:22:26 [ERROR] unable to load config, waiting 5 seconds before exiting...
2026/03/09 09:22:31 [FATAL] error unmarshaling YAML data: [46:5] unknown field "audio"
  43 |     realtime: false
  44 |     share: false
  45 |   preview:
> 46 |     audio: true
�
           ^
  47 |     autoplayMedia: false
  50 |     

I also found a Typo in your Documentation on Conditional Rules - Global Flags Page.

It says:

sources:
  - path: "/data"
    config:
      rules:
        - FolderPath: "/"             # (global)
          ignoreHidden: true          # ignores all hidden
        - FolderPath: "/"             # (global)
          ignoreZeroSizeFolders: true # ignores all zero size folders
        - FolderPath: "/"             # (global)
          ignoreSymlinks: true        # ignores all symlinks

But the Log comes with "FolderPath" unknown field.
It has to be "folderPath"

With all of this out of the way Filebrowser is running again.

[Cetheus]

Now I'm facing a new Problem...
I don't get the Sources. Even when all is configured and the Log shows the right Sources, I don't get the Content.

[gtsteffaniak]

Are your sources configured to be enabled by default via defaultEnabled?

https://filebrowserquantum.com/en/docs/configuration/sources/#single-source

By default, a user needs to be granted access to the source to be able to view it, done by an admin.

[Cetheus]

Hmm ok. It was set to false because of the description "Should be added as a default source for new users?"
Thank you for your help. I appreciate it.