Collaboration with external partners, customers, or service providers has become a critical part of modern business. Almost every company works on joint projects, relies on external consultants, or partners with suppliers who need access to corporate information and collaboration platforms. Microsoft Teams has become the de facto hub for teamwork and offers a B2B guest access feature to invite external users.
In practice, however, things often look different: Not every organization allows the use of Teams’ built-in guest feature. Strict security policies, industry compliance requirements, or internal IT guidelines often prohibit enabling external identities in the directory.
Instead, many companies take a different route: They create internal user accounts for external people. These are full-fledged user accounts in the organization’s directory but are only assigned to external collaborators. To distinguish them from real employees, organizations often use a prefix such as “EXT_” or “GUEST_”.
It’s important to note: this approach is not always just a workaround. In many organizations, it’s a necessity. The reason is simple: Some corporate applications do not support guest identities at all. For example, if an external consultant needs access not only to Teams but also to an internal ERP or HR system, those applications may only allow logins via standard user accounts. In such cases, the only option is to create an internal account for the external partner.
This is how the so-called internal guests are created: external individuals who use internal accounts to collaborate in Microsoft Teams and beyond.