Root cannot access a directory - access denied

Under Linux (Ubuntu 14LTS), I'm trying to access an encrypted local directory created by a regular user (encfs) as root, but I get access denied:

root@toad:/home/robert# cd inbox
bash: cd: inbox: Permission denied
  1. How is it possible?
  2. How to allow other users to access it?

Solution 1:

encfs is a FUSE (File system in user space) file system. Access to FUSE file systems is usually limited to the user that mounted it by the kernel, but it can be granted to others with the allow_other and allow_root mount options (mount_fuse manpage). This is somewhat similar to NFS file systems that can't be access by root if they are exported with root_squash.