[Migrated from MSDN Exchange Dev] Office 365 users are restricted to a 10MB attachment Limit

Joyce Shen - MSFT 16,641 Reputation points

[Note] This thread was originally posted on MSDN. As the MSDN Exchange Dev forum mainly focuses on developing issues and the TechNet Exchange forums for general questions have been locked down, we manually migrated this one to Microsoft Q&A platform to continue the troubleshooting.

[MSDN thread link] Office 365 users are restricted to a 10MB attachment Limit

We currently have a hybrid setup of Exchange 2013 and Office 365.

Our 365 users are unable to receive attachments larger than 10MB. I have looked everywhere and assume the issue lies within the transportconfig setting our ExternalDsnMaxMessageAttachSize and InternalDsnMaxMessageAttachSize at 10MB

In our On prem exchange I can change these values, however in 365 it appears as though they have deprecated the commands to change these values.

Does anyone know how I can remedy this situation?

Microsoft Exchange Hybrid Management
Microsoft Exchange Hybrid Management
Microsoft Exchange: Microsoft messaging and collaboration software.Hybrid Management: Organizing, handling, directing or controlling hybrid deployments.
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  1. Joyce Shen - MSFT 16,641 Reputation points


    Please refer to the official article which introduces about setting message size limit in Exchange online: Office 365 now supports larger email messages—up to 150 MB


    Some related links below for your reference as well:

    Message limits
    Configuring Max Email Message Size Limits for Office 365

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