Modify Office 365 Message Size Limit

With the support of up to 150MB email message size, large number of enterprise are now looking for migration to Office 365. Previously 35MB message size limit was a show stopper for large number of organization looking for migration options.

Recently i got a chance to work for a customer who has a message size limit of 100MB for their users in their current environment and would like to use the same size limits in Office 365.

You’ve couple of options available to modify office 365 message size limit to help your customers.

  1. Modify Office 365 Message Size Limit for Individual User
  2. Modify Office 365 Message Size Limit for all the Users

 

Modify Office 365 Message Size Limit for Individual User is only recommended for organizations where you want to modify send/receive limit for specific group of user.

Let’s see how we can modify Office 365 message size limit with each option.

Modify Office 365 Message Size Limit for Individual User

At times, we’ve seen requirements where individual user requires to send or receive large size attachments to internal or external recipients. In order to allow these users to send/receive large size emails, we need to modify the size limits for these specific users. Below are the steps to do so.

  1. Login to Office 365 using Global Admin account
  2. Navigate to Admin –> Exchange –> Recipients –> Mailboxes
  3. Search for the user mailbox
  4. Select the user mailbox and click on Edit
  5. In Mailbox properties, click on Mailbox Features
  6. Click on View Details under Message Size Restrictions
  7. Default Message Size Restrictions are 35 MB for send and receive. Modify the settings based on your needs.
  8. I’ve modified the message size restrictions to 100MB for my user account.

Modify Office 365 Message Size Limit

Modify Office 365 Message Size Limit for all Users

Few companies for whom I’ve worked have specific requirements around message size limits like Marketing and Financial Institutes. To modify Office 365 message size limit for all users, we need to rely on PowerShell for Office 365 as modifying Office 365 message size limit for all users using Exchange Admin Center can be a hectic process based on user count that you’ve. Following are the steps to modify Office 365 message size limit for all users using PowerShell.

  • Connect PowerShell with Exchange online.

You can use the PowerShell script to connect with Exchange Online. Script can be downloaded from Microsoft TechNet Gallery.

  • Run the cmdlet Get-MailboxPlan | fl Name, IsDefault to see a default MailboxPlan.

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  • Notice the name of default policy that is applied to all users.
  • Run the following cmdlet to set the message size limit

Set-MailboxPlan ExchangeOnlineEnterprise-33fbd11f-ba2c-460a-bc4c-1ac95fd85e70 -MaxSendSize 1
00MB -MaxReceiveSize 100MB

3

 

  • To verify the configuration, run the cmdlet Get-MailboxPlan | fl Name, IsDefault, MaxSendSize, MaxReceiveSize

4

  • You can see that the default message size limits have been changed to 100MB for all users.

Please note that if you can setup maximum message size limit of 150MB. If you try to set a value larger then 150MB then you’ll receive an error message that says the value is not within the define range.

Conclusion

Office 365 message size limit is a good option for many of the customers to allow them to move to Office 365 and configure these settings for all or specific users based on requirements. I do recommend to review your needs for message size limits before you modify the limits. Large message size limits can cause significant impact on your end user productivity as well due to any reason like network bottleneck or recipient domain do not accept larger attachments etc. It’s always good to define the business needs first then modify the system to fulfill the requirements without impacting the end user productivity.