By default Office 365 message size is set to 25 MB. Below are commands on how to change the message size limits in Powershell. Please note in OWA you can only set it to a maximum to 75 MB unlike an Outlook client where you can set it to 150 MB.

Instructions on How to Change Office 365 Message Size Limits:

Connect to Exchange Online using the Windows Azure Powershell Module.

Below are scripts where you can modify a single user, by CSV, the whole organization and the MailboxPlan.

Modify Max receive and send by CSV:

Import-CSV “C:\temp\Filename.csv” | foreach {Set-Mailbox -identity $_.User -MaxSendSize 75MB -MaxReceiveSize 75 MB} 2>> c:\temp\FileNameLogs.txt

Example of CSV:

example snippet of a csv document

Modify A Single User:

Set-Mailbox -Identity [email protected] -MaxSendSize 75MB -MaxReceiveSize 75MB 

Modify All Users:

Get-Mailbox | Set-Mailbox -MaxSendSize 75MB -MaxReceiveSize 75MB 

Modify The MailBoxPlan For Future Users:

Get-MailboxPlan | Set-MailboxPlan -MaxSendSize 75MB -MaxReceiveSize 75MB

If you have questions about this Tech Tip on how to change Office 365 Message Size Limits in Powershell, please contact us.  If you would like to see us share a Tech Tip on another issue you are having, leave a comment on our FacebookTwitter or LinkedIn page with #TechTip and we’ll cover it in one of our future Tips & Tricks by MessageOps.

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