There are two types of users in ShareSync, depending on the way they have been added for folder sharing:

 Adding users to the account via CONTROL PANEL

In order to set up a collaborative folder share, Admin needs to create a new ShareSync user in CONTROL PANEL. User’s own email address should be entered in the Email Address (login) field to ensure that all email-based notifications generated by ShareSync are delivered to the end user. The email address may be hosted by any 3rd party company.
cpanel

Once the user is created, they will have full access to all desktop, mobile and web apps.

 ShareSync users can invite external collaborator with/without administrator's approval

To set it up:

  1. Make sure External Sharing is enabled on the Services > ShareSync > Settings page:
    Settings
  2. On the Services > ShareSync page, check the Invite External Users box:
    Settings

If you choose to approve end-users' requests, you will do it the following way:

requests

This is how external collaborators appear in your user list in CONTROL PANEL:

userlist

Comparing Regular users and External Collaborators

  Regular ShareSync user External Collaborator
occupy ShareSync disk space + +
can use all ShareSync clients (desktop and mobile) + +
can create folders + +
can upload own files + +
can be granted with the following level of permissions to folder view, modify, co-owner view, modify
can have any domain name + should have an external domain name for the company, that doesn't use ShareSync
can set permission-based sharing + -
can share via link + -
increase monthly charges for ShareSync according to the billing plan + -
increase account total disk space according to the billing plan + -
can login in My Services + +
can restore password using Forgot password? on Unified Login Page + +
can restore trashed content + +
apply backup policies + Can synchronize only My ShareSync folder