MS-900 Practice Question: Describe Microsoft 365 pricing, licensing, and support
A user is unable to send emails with attachments larger than 25 MB. The organization has Microsoft 365 Business Standard. What should you do to increase the attachment limit?
⚠ Common exam trap
A common mix-up: candidates confuse the 25 MB default limit with a hard-coded protocol restriction (like SMTP's theoretical limit), leading them to choose workarounds like compression or OneDrive instead of recognizing that the limit is an administrative policy configurable in the Exchange admin center.
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
✓
Modify the maximum message size in the Exchange admin center
In Microsoft 365 Business Standard, the default maximum message size for email attachments is 25 MB. To increase this limit, you must modify the maximum message size setting in the Exchange admin center (EAC), which controls the transport limits for the organization. This is the correct administrative action to raise the attachment size threshold beyond the default.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Modify the maximum message size in the Exchange admin center
Why this is correct
The correct solution is for an administrator to raise the organization's transport limit in the Exchange admin center (Mail flow > Message size limits). Exchange Online allows configuration of the maximum send/receive message size up to 150 MB, so changing this setting directly raises the attachment ceiling. Since the user was blocked by the default 25 MB policy, only this change at the service level resolves the issue for all users in the organization.
- ✗
Instruct the user to compress the file
Why it's wrong here
Compressing the file with a utility like 7-Zip or WinZip may shrink it below the 25 MB threshold, but it does not alter the Exchange Online organization-wide message size limit. If the compressed file still exceeds the limit, or if the file type is already compressed (for example, MP4 or PDF), the email will still be rejected. This approach is purely a user-side workaround and does not satisfy the requirement to increase the attachment limit.
- ✗
Purchase an Exchange Online Kiosk add-on
Why it's wrong here
Purchasing an Exchange Online Kiosk add-on is unrelated to attachment size limits. The Kiosk plan is designed for lightweight shared-mailbox scenarios, offering a small 2 GB mailbox and no desktop Outlook client, so it cannot raise the 150 MB transport cap or any per-message size limit. Adding this license would incur extra cost and still leave the default 25 MB message size restriction in force, making it an entirely ineffective fix.
- ✗
Have the user upload the file to OneDrive and share a link
Why it's wrong here
Uploading the file to OneDrive and sharing a link is a practical collaboration workaround, but it does not increase the Exchange Online message size limit. When the user sends a link, the file is not transmitted through the Exchange pipeline as an attachment, so the policy is bypassed rather than changed. If the requirement is to increase the maximum allowed attachment size for email, this action fails to modify the transport configuration, even though it is a valid alternative for sharing large files.
Go deeper
Related to this question
Learn chapter
Microsoft 365 Admin Roles and Permissions
Key term
Exchange admin center
The Exchange admin center (EAC) is a web-based management console used by IT administrators to manage email, calendars, contacts, and other mail-related features in Microsoft Exchange Server or Exchange Online.
Key term
Microsoft 365
Microsoft 365 is a subscription-based cloud service from Microsoft that combines productivity tools like Office apps with security, device management, and online storage.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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