EACCES: permission denied, mkdir error when using bind mounts

[Nikojiro]

Describe the bug

Hi,

I'm trying to install a local instance of Sync-in on Ubuntu Server.

I've used bind mounts to local folders instead of volumes. I'm running sync-in server with PUID:GUID matching the ownership of my root data folder:

#include:
#  - ./config/nginx/docker-compose.nginx.yaml
#  - ./config/onlyoffice/docker-compose.onlyoffice.yaml
#  - ./config/collabora/docker-compose.collabora.yaml
#  - ./config/sync-in-desktop-releases/docker-compose.sync-in-desktop-releases.yaml

name: sync-in
services:
  sync_in:
    image: syncin/server:2
    container_name: sync-in
    restart: always
    environment:
      - INIT_ADMIN
      - INIT_ADMIN_PASSWORD
      - INIT_ADMIN_LOGIN
      - PUID=110
      - PGID=1008
    ports:
      - "6080:8080"
    volumes:
      - ./environment.yaml:/app/environment/environment.yaml
      - /media/sync-in/app:/app/data
      - desktop_releases:/app/static/releases:ro
    depends_on:
      - mariadb
    logging:
      driver: json-file
      options:
        max-size: "25m"
        max-file: "5"
    networks:
      - sync_in_network

  mariadb:
    image: mariadb:11
    container_name: mariadb
    restart: always
    command: --innodb_ft_cache_size=16000000 --max-allowed-packet=1G
    environment:
      MYSQL_ROOT_PASSWORD: SuperSecret
      MYSQL_DATABASE: sync_in
    volumes:
      - /media/sync-in/db:/var/lib/mysql
    networks:
      - sync_in_network

networks:
  sync_in_network:
    driver: bridge

volumes:
  desktop_releases:

When I try to log in with the admin account, I get the following error:

[2026-04-01 08:35:24] ERROR (124): [ExceptionsHandler] <admin> EACCES: permission denied, mkdir '/media/sync-in' | req-14

    err: {

      "type": "Error",

      "message": "EACCES: permission denied, mkdir '/media/sync-in'",

      "stack":

          Error: EACCES: permission denied, mkdir '/media/sync-in'

              at async Object.mkdir (node:internal/fs/promises:856:10)

              at async UserModel.makePaths (/app/server/applications/users/models/user.model.js:113:17)

              at async UsersManager.logUser (/app/server/applications/users/services/users-manager.service.js:64:13)

              at async AuthProviderMySQL.validateUser (/app/server/authentication/providers/mysql/auth-provider-mysql.service.js:42:16)

              at async AuthLocalStrategy.validate (/app/server/authentication/guards/auth-local.strategy.js:32:22)

              at async AuthLocalStrategy.callback [as _verify] (/app/node_modules/@nestjs/passport/dist/passport/passport.strategy.js:13:44)

      "errno": -13,

      "code": "EACCES",

      "syscall": "mkdir",

      "path": "/media/sync-in"

    }

[2026-04-01 08:35:24] ERROR (124): [HTTP] <unauthorized> POST /api/auth/login (HTTP/1.1 500) 192.168.1.106 (52 bytes in 81ms) Mozilla/5.0 (X11; Linux x86_64; rv:149.0) Gecko/20100101 Firefox/149.0 | req-14

    err: {

      "type": "Error",

      "message": "failed with status code 500",

      "stack":

          Error: failed with status code 500

              at onResFinished (/app/node_modules/pino-http/logger.js:115:39)

              at ServerResponse.onResponseComplete (/app/node_modules/pino-http/logger.js:178:14)

              at ServerResponse.emit (node:events:520:35)

              at onFinish (node:_http_outgoing:1026:10)

              at callback (node:internal/streams/writable:764:21)

              at afterWrite (node:internal/streams/writable:708:5)

              at afterWriteTick (node:internal/streams/writable:694:10)

              at process.processTicksAndRejections (node:internal/process/task_queues:89:21)

    }

Why on earth is there a try to mkdir /media/sync-in? The directory exists.

Thanks for helping.

Installation method

Docker Compose

System information

Sync-in version: 2
OS: Ubuntu Server 24.04.4 LTS
Filesystem: BTRFS

Reproducible on demo?

No

Logs (server or browser)

[7185]

The directory /media/sync-in exists on the host, not in the container. You probably set that as a dataPath, please set dataPath to /app/data instead.

[Nikojiro]

You're absolutely right, and I'm being particularly dumb today ^_^

Didn't pay attention enough that environment.yaml is bind mounted.

Fixed, my server is up.

Thanks for the help!