How to Change maximum Office 365 attachment size with PowerShell

The default Office 365 maximum message size for messages is 35MB. Because the email text is usually small, this setting essentially restricts the maximum attachment size. You can change the maximum message size for an individual mailbox in the Office 365 admin center or with PowerShell.

To check the current message sending/receiving limt

Get-Mailbox -Identity “UserName@YourDomain.com” | fl maxsendsize,maxreceivesize

To set the message sending/receiving limit to 150 MB

Set-Mailbox -Identity “UserName@YourDomain.com” -MaxReceiveSize 150MB -MaxSendSize 150MB

How To Change Office 365 Message Size Limit Using Web Console

Change Office 365 Message Limit for one mailbox

Step 1. Open Exchange Admin

Once logged in to your Office 365 portal click on Admin on then left menu bar and then Exchange to open the Exchange Admin

Step 2. Open the Recipients Mailbox Properties

Click on Recipients in the left side bar, click on the Individual Mailbox and then click on the edit icon.

Step 3. Change the Message Size Limit

Click on Mailbox Features and then scroll down to Message Size Restrictions.  Click on View details

Step 4. Change the Maximum Message Size

Change the Maximum Message size up to a maximum of 150000KB for Sent and Received message

Office-365-Maximum-Message-Size-Limit

Change Office 365 Message Limit for All New Accounts

Step 1. Open Exchange Admin

Once logged in to your Office 365 portal click on Admin on then left menu bar and then Exchange to open the Exchange Admin

Step 2. Change the Default Message Size Limit

In the mailbox view click on the … and then click on Set Default Message Size Restrictions.

Office-365-Set-Default-Message-Size-Restrictions