Understand the differences and limitations of what a managed user can do, what an external user can do and what an unmanaged user is.
A managed user is most often someone who has been created within your admin console. As an admin or co-admin, you can edit, delete, enforce security settings, and run activity reports on these users. Any files these users upload into folders they own will count against your total storage allocation.
More information on creating and editing Managed Users:
An unmanaged user is someone who uses an unpaid personal Box account that is still part of your organization's managed domain -- for example, harrypotter@ABCcompany.com. Although they are within your organization’s managed domain, they do not belong to your Box enterprise; their Box accounts are unlicensed. Most important, unmanaged users increase your security and compliance risk because their accounts are not constrained by your enterprise's Box security policies. With the help of the User Details report, you can identify your unmanaged users and close this security gap by inviting them en masse to become managed users.
An external user is someone who has a Box account that was not created directly from within your own Box Admin Console. While you can share and collaborate with external users, your management capabilities over external user accounts are limited to the folders nto which you have invited them.
With certain paid accounts, both external users and managed users contribute towards your overall purchased user seat count. Business Plus, Enterprise, and Elite accounts have unlimited external collaboration, so only managed users contribute to your seat count.
External users may or may not also be unmanaged.
For further information, visit our Managing Users Best Practice.