Internal Guests in Microsoft Teams – Why They Exist and the Challenges

The Challenges of Internal Guests in Microsoft Teams

While internal guest accounts solve a practical problem, they create significant challenges — especially because Microsoft Teams treats them like normal employees.

Missing Guest Label

Regular B2B guests in Teams are clearly labeled with the suffix “Guest”. Internal guest accounts, however, appear as members. At first glance, there’s no indication that these accounts actually belong to external individuals.

This lack of transparency creates a blind spot: a team owner looking at the member list cannot easily distinguish between employees and external users.

Risk of Confusion with Employees

Because internal guests are treated as members, they can easily be mistaken for employees. As a result, they often receive more privileges than they should. Without a clear distinction, external users may gain access to documents and conversations that were never intended for them.

No Expiration Dates

By default, internal guest accounts remain active until they are manually removed. There is no built-in lifecycle or expiration mechanism. In reality, these accounts are often forgotten after a project ends. Months later, external individuals may still have access to Teams, files, and even sensitive applications. This creates both security risks and compliance violations.

High Administrative Overhead

Because Teams provides no built-in way to separate internal guests from employees, administrators are left to manage them manually. They rely on Excel lists, naming conventions, or custom scripts to keep track of who is an employee and who is an external partner. The larger the organization, the harder this gets.

Inconsistent Behavior in Applications

Some applications treat internal guests like full employees, others block them. This inconsistency leads to confusion for users and additional work for IT.

A Necessity Rather Than an Exception

Many organizations would prefer to rely on standard guest access. But as long as critical business systems require internal accounts, internal guests are here to stay. They are not the exception — for many companies, they are an integral part of collaboration. This makes it all the more important to manage them securely and transparently.

New Valprovia Teams Center Feature Solves the Problem

To address these gaps, we have developed a new Teams Center feature specifically designed for managing internal guests. The goal: allow organizations to manage internal guests as if they were regular guests, with all the transparency, control, and lifecycle management capabilities that are otherwise missing.

Flexible Identification

Internal guests can now be automatically identified in two ways:

1. Prefix in the username – for example, “EXT_” or “GUEST_”.

2. Active Directory profile property – such as a custom attribute in Azure AD that marks the user as external.

This gives organizations flexibility: they can rely on naming conventions, directory attributes, or a combination of both to classify internal guests.

Consistent Treatment as Guests

Once identified, these accounts are automatically flagged and treated as guests — even though they are technically internal users. They show up in the same overviews, reports, and processes as standard B2B guests. This ensures transparency: everyone can clearly see that these are not employees.

Central Guest Management

All guest accounts — whether created through B2B invitations or internal guest accounts — are displayed in a single unified view. Administrators and team owners finally gain full visibility into who the external users are and where they have access.

Time-Bound Access

A key capability is the ability to assign expiration dates to internal guests. When the date is reached, access is automatically revoked unless explicitly extended.

This eliminates the risk of forgotten guest accounts. Projects may end, deadlines may slip — but access rights remain under control.

Self-Service for Team Owners

Team owners are empowered to manage their own guests. They can see exactly which internal guest accounts are part of their team and how long their access remains valid. With a few clicks, they can extend or remove access. Meanwhile, the system ensures that expired accounts are blocked automatically, so nothing is overlooked.

Real-World Scenarios

Example 1: Financial Institution with External Consultants

A bank works with a consulting firm on a regulatory project. Company policy prohibits inviting B2B guests. The consultants receive internal accounts with the prefix “EXT_”.

Previously, these accounts were indistinguishable from employees in Teams. Many remained active long after the project ended.

With the new Teams Center feature:

• All “EXT_” accounts are automatically identified as internal guests.

• Team owners see them clearly labeled as guests.

• Expiration dates ensure timely removal unless access is extended.

The result: greater security, less manual work, and full transparency.

Example 2: Manufacturing Company with External Developers

A manufacturing firm collaborates with an external software team. The developers not only need access to Teams but also to an internal production planning system that doesn’t support B2B guests. Internal accounts are unavoidable.

The new feature ensures these accounts are still recognized as guests, subject to lifecycle management and expiration policies. This allows the company to meet both the technical requirements of its systems and its governance standards.