Using curlftpfs, encfs, sshfs etc. in Linux as a normal user can result in the following error message:

fusermount - failed to open /etc/fuse.conf - Permission denied

Explanation

The error occurs, because only root and members of the group fuse have the permissions which are required to run these commands.  To confirm that this is the root of your problem, enter the following in a terminal:

groups <username>

You will get a list of groups you are a member of and “fuse” will most likely be missing. If it is a different user who has the problem, just use his/her username.

Solution

The problem can be easily fixed by adding the user to the fuse group:

sudo addgroup <username> fuse

(Replace <username> with your username or the the username of the user you want to add to fuse)

After that, if the user is currently logged in, the user needs to log out and back in for the changes to take effect. The changes can be confirmed running

groups <username>

again. “fuse” should now be listed.