The default mail size limit of Office 365 mailbox is 25 MB and we can increase that limit to up to 150 MB. This is required because sometime we may need to attach some files which may be of our 25 MB. In that case we would not be able to send or receive emails. So to deal with this situation we can increase overall message size limit of Office 365 mailbox. So in this guide we learn how to Increase Mail Size in Office 365 Mailbox so that we can even upload large size attachments. Just follow the below mentioned steps:

Video Guide:

Step 1: Login to Office 365 account and Click on Admin >> Exchange


Step 2: Click on Recipients >> mailbox >> select the mailbox and click on 3 dots >> select Set default message size restriction 


Step 3: Now you can enter the maximum size of sent as well as received message.



We can also use this method to restrict the mail size limit for some users of our office 365 account. 

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