The correct approach is to perform a cross-tenant mailbox migration. This method is specifically designed to consolidate Microsoft 365 tenants while minimizing user disruption and retaining existing email addresses, as it moves mailboxes between tenants while preserving primary SMTP addresses and all associated mailbox data natively. On the MS-102 exam, this scenario tests your understanding of native Microsoft 365 migration tools versus third-party or hybrid solutions; a common trap is choosing a domain-based migration or a simple cutover, which would require users to change their email addresses or cause downtime. Remember the key distinction: cross-tenant mailbox migration keeps the same email address for each user, whereas other methods often force an address change. A helpful memory tip is "Cross-Tenant Keeps the Address Intact"—or simply "CT-KAI."
MS-102 Deploy and manage a Microsoft 365 tenant Practice Question
This MS-102 practice question tests your understanding of deploy and manage a microsoft 365 tenant. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company has recently acquired a smaller organization and needs to consolidate both Microsoft 365 tenants. They want to minimize user disruption and retain existing email addresses. Which approach should they use?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "minimum / minimize"
Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Perform a cross-tenant mailbox migration
Option B is correct because cross-tenant mailbox migration allows you to move mailboxes between two Microsoft 365 tenants while preserving the users' existing email addresses and minimizing disruption. This approach uses the Microsoft 365 native migration capabilities, specifically the cross-tenant mailbox migration feature, which supports moving mailboxes with their primary SMTP addresses and associated data without requiring on-premises Exchange Server.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Configure a hybrid deployment with Exchange Server
Why it's wrong here
Hybrid deployment is for on-premises Exchange integration, not tenant-to-tenant migration.
✓
Perform a cross-tenant mailbox migration
Why this is correct
Cross-tenant migration moves mailboxes and retains email addresses, minimizing disruption.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Delete all users from the acquired tenant and recreate them in the parent tenant
Why it's wrong here
This causes significant disruption and data loss.
✗
Set up a federation trust between the tenants
Why it's wrong here
Federation does not consolidate tenants; it allows authentication sharing.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse cross-tenant mailbox migration with federation trust or hybrid deployment, assuming that any inter-tenant connectivity solution can consolidate mailboxes, but only the cross-tenant migration feature directly moves mailbox data while preserving email addresses.
Detailed technical explanation
How to think about this question
Cross-tenant mailbox migration uses the `Start-MigrationBatch` cmdlet with the `-CrossTenant` parameter and requires configuring an organization relationship between the source and target tenants with the `EnableMailboxMove` flag set to `$true`. The migration preserves the user's Exchange GUID and archive mailbox linkage, ensuring seamless transitions for clients like Outlook and mobile devices. In real-world scenarios, this approach is critical for mergers and acquisitions where retaining the original SMTP addresses is a legal or business requirement.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this MS-102 question in full detail.
Deploy and manage a Microsoft 365 tenant — This question tests Deploy and manage a Microsoft 365 tenant — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Perform a cross-tenant mailbox migration — Option B is correct because cross-tenant mailbox migration allows you to move mailboxes between two Microsoft 365 tenants while preserving the users' existing email addresses and minimizing disruption. This approach uses the Microsoft 365 native migration capabilities, specifically the cross-tenant mailbox migration feature, which supports moving mailboxes with their primary SMTP addresses and associated data without requiring on-premises Exchange Server.
What should I do if I get this MS-102 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Contoso recently acquired a company with an existing Microsoft 365 tenant. You need to migrate their user accounts and mailboxes to the Contoso tenant. The acquired company uses a custom domain for email. You must ensure minimal disruption and maintain email flow during migration. What should you do first?
medium
A.Perform a cross-tenant mailbox migration using Microsoft 365 migration tools.
B.Disable the acquired company's tenant to force all users to the Contoso tenant.
C.Create new user accounts in the Contoso tenant using the onmicrosoft.com domain.
✓ D.Add the custom domain to the Contoso tenant and verify ownership.
Why D: Before any migration can proceed, the custom domain used by the acquired company must be added and verified in the Contoso tenant. This is a prerequisite for cross-tenant mailbox migrations because the target domain must be recognized and owned by the destination tenant to route email correctly and assign user principal names (UPNs). Without domain verification, migration tools cannot validate the domain and email flow will fail.
Variation 2. Your company recently acquired a subsidiary that uses a different Microsoft 365 tenant. You are tasked with merging the two tenants into one. The subsidiary has 1,500 users with unique email domains. You need to migrate all users, mailboxes, and SharePoint data while minimizing downtime and preserving data integrity. You have access to both tenants as global admin. What should you do first?
hard
A.Add the subsidiary's domain to the primary tenant, then delete the subsidiary tenant and recreate users
B.Use the Microsoft 365 Merger Center in the admin portal
✓ C.Use a third-party migration tool such as BitTitan MigrationWiz to perform the migration
D.Use Microsoft's native tenant-to-tenant migration by moving mailboxes via PowerShell and exporting SharePoint content
Why C: Option C is correct because Microsoft does not provide a native tool for merging two tenants; third-party tools like BitTitan MigrationWiz are designed specifically for cross-tenant migrations, supporting mailbox, SharePoint, and user data migration with minimal downtime and data integrity. These tools handle directory synchronization, mailbox rehydration, and SharePoint content mapping, which are critical for a 1,500-user migration with unique domains.
Last reviewed: Jun 24, 2026
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