MS-900 Describe Microsoft 365 apps and services Practice Question
Contoso Ltd. is a medium-sized company with 2,000 users. They use Microsoft 365 E5 and have recently deployed Microsoft Teams for collaboration. The IT department has received complaints that external partners (guests) can see internal team names and member lists in the Teams directory. The compliance team requires that external guests must only see teams they are directly added to, and they must not be able to search for other teams or see internal team members who are not members of the same team. Additionally, the HR team wants to use a custom app in Teams that allows employees to submit leave requests, and this app must be available to all employees without requiring them to install anything manually. The IT admin needs to configure Teams settings to meet these requirements. Which two actions should the admin take? (Choose two. Each correct answer is part of the solution.)
⚠ Common exam trap
A common mix-up: candidates confuse 'external access' (federation for chat/calling) with 'guest access' (B2B collaboration for team membership), leading candidates to select options that manage federation settings instead of the specific Teams directory visibility control.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Disable 'Show all teams' in the Teams admin center to prevent guests from seeing teams they are not members of.
Disabling 'Show all teams' in the Teams admin center (under Teams settings) prevents guests from seeing teams they are not members of in the Teams directory. This directly addresses the compliance requirement that external guests must only see teams they are directly added to and cannot search for other teams or see internal team members outside their own team.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Disable 'Show all teams' in the Teams admin center to prevent guests from seeing teams they are not members of.
Why this is correct
Disabling the 'Show all teams' tenant-wide setting in the Teams admin center controls whether users, including guests, can browse all teams in the organization and request to join them. When this setting is off, guests only see the specific teams they have been added to, which directly satisfies the security requirement. Unlike external access or SharePoint sharing, this setting specifically targets team discovery and visibility.
- ✓
Create a Teams app setup policy that pins the leave request app for all users.
Why this is correct
An app setup policy in the Teams admin center defines the apps that are automatically pinned to the app bar for users in a policy assignment. By creating and assigning a policy that pins the leave request app to all users, the app will appear in the left-hand navigation, giving employees efficient access without requiring navigation to the app catalog. This is the correct administrative method to deploy and surface a line-of-business app across the organization.
- ✗
Block all external access in Teams admin center to prevent guests from joining.
Why it's wrong here
Blocking external access in Teams admin center disables federation with other organizations, meaning users from different domains cannot find and communicate with users in Contoso. However, guests are invited via Microsoft Entra ID Business-to-Business (B2B) collaboration, which is a distinct identity mechanism that grants access to specific teams. Therefore, turning off external access will not prevent guest users from seeing or joining teams; instead, it only blocks cross-tenant communication.
- ✗
Configure external sharing settings in SharePoint admin center to limit guest access.
Why it's wrong here
Configuring external sharing settings in the SharePoint admin center governs how users can share sites and documents with people outside the organization, such as anonymous sharing or inviting external users as site members. This setting applies to SharePoint and OneDrive file-level collaboration, not to the Teams app experience or the visibility of team channels. The requirement about guests seeing teams they are not members of is managed within the Teams admin center, not via SharePoint's external sharing controls.
- ✗
Enable external access in Teams admin center to allow guests to communicate with internal users.
Why it's wrong here
Enabling external access in the Teams admin center is used to allow your users to chat and set up meetings with users in other Microsoft Entra ID tenants; this is known as federation and does not create guest accounts in Contoso. Guests are identity records added to your tenant, and they already have the ability to communicate with internal users once they are added to a team. This setting would broaden your organization's communication boundary rather than restrict guest visibility, so it does not address the stated requirement.
Go deeper
Related to this question
Learn chapter
Retention Labels and Compliance
Key term
Teams admin center
The Teams admin center is a web-based management portal where IT administrators control settings, users, policies, and features for Microsoft Teams across an organization.
Key term
Collaboration
Collaboration in Microsoft 365 refers to the integrated tools and services that enable people to work together in real time, share information, and coordinate tasks from anywhere.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This MS-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the MS-900 exam.