You have successfully deployed a file browser container using Docker on the SecureEdge Pro and the web interface is accessible. However, when you attempt to upload, modify, delete, or create new files and folders within your mapped directories, the action fails. You might see "403 Permission denied" errors in the container logs or the web interface simply refuses to accept changes, acting as if the volume is mounted as read-only.

This is a classic Docker permission mismatch. Originally, processes inside a Docker container run as the root user. However, many modern and secure Docker images are configured to step down from root and run their internal processes as a restricted user for security purposes.

When you map a host directory to a container volume, the container tries to write to that host directory using its internal user ID (UID) and group ID (GID).

If the container's internal UID/GID does not have write permissions to the folder on your host machine, the host OS will block the action. Older versions of the Filebrowser image or custom builds might also lack the necessary internal mechanisms to smoothly remap these permissions on startup.

To fix this, you need to increase the permissions of the file browser container by explicitly telling the container which User ID (PUID) and Group ID (PGID) it should use when interacting with the host system. This is done by updating the container to use a modern process supervisor (like the latest s6-overlay) and passing specific environment variables.

In the below example, a container is configured to run with root permissions (PUID 0 and PGID 0) to ensure it has unrestricted write access to the mapped volumes.

Step 1: Ensure you are using an updated image

Make sure your deployment is using a file browser image that supports the latest s6-overlay architecture. The s6-overlay acts as an init system inside the container, intercepting the PUID and PGID variables to correctly adjust file ownership and permissions before launching the file browser application. Using the link below, and appending the "-s6" to the tag usually ensures that you have the latest container version with the s6-overlay.

Run the following commands from your desktop. Example image: https://hub.docker.com/r/filebrowser/filebrowser/

sudo docker pull filebrowser/filebrowser:v2.60.0-s6 --platform linux/arm64/v8
sudo docker tag filebrowser/filebrowser:v2.60.0-s6 192.168.140.1:5000/filebrowser:v2.60.0-s6
sudo docker push 192.168.140.1:5000/filebrowser:v2.60.0-s6

Step 2: Update your Docker configuration

You need to pass PUID=0 and PGID=0 environment variables into your container's environment when creating the Docker container from the pushed image. Add  two entries:

Key=PUID Value=0
Key=PGID Value=0