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How to Increase Mailbox Size Office 365 in 2024? A Guide to Follow

Published By Ashwani Tiwari
Tej Pratap Shukla
Approved By Tej Pratap Shukla
Published On March 15th, 2024
Reading Time 5 Minutes Reading

Summary: Have you ever encountered the Office 365 Mailbox Size Exceeded alert? If this happens to you, then your mailbox has either stopped bringing in new mail or will soon cease to. Keep on reading to know how to deal with this problem and learn ways to increase Office 365 mailbox size.

Table of Content

Microsoft offers various plans for Office 365. The size of their mailboxes differs as per the plan you have subscribed to. As most users prefer storing their data on cloud platforms, more space is required.

Some plans offer 50 GB, while others like Enterprise E5 offer 100 GB of storage space. So how can you increase Office 365 mailbox size to 100GB? You are left with two options here. One is to upgrade your plan and the other one is to copy email from Office 365 to your Desktop and delete your mailbox data items.

User Query

“I have a subscription plan of O365 business premium which offers only 50 GB space. But now after having consumed every bit of it, I need more cloud storage to continue my work. How can I get rid of the Office 365 mailbox size exceeded error?”

Office 365 Increase Mailbox Size to 100 GB – How to Do It?

The easiest method is to delete unwanted items from your account. You can delete documents, emails, etc. that you do not need anymore. But before doing that, you must create a local copy of your mailbox data on your computer for future use.

Backing up your data is essential to protect it against any ransomware attacks or accidental deletion. You can always access your data even during the downtime of servers. As Microsoft does not take the responsibility of protecting your data, you completely have to secure it.

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Office 365 Backup Tool is one such software that is used by the majority of businesses to secure their data. With its help, you can always backup and restore the data from and to your Office 365 account. After creating a copy of your crucial data, you can use the PowerShell commands to fix the Office 365 mailbox size exceeded error.

5 Simple Steps for Office 365 Increase Mailbox Size Limits 

  • Step 1. Download & Launch Software on PC.
  • Step 2. Set-Mailbox Categories & Apply Filter. 
  • Step 3. Login with Office 365 Admin Credentials. 
  • Step 4. Set Destination Path & Location on PC. 
  • Step 5. Validate Permission & Click on Start.

How to Increase Office 365 Mailbox Size Using PowerShell?

Windows PowerShell commands are a powerful utility to help you increase your size. Follow the below-given methods to fix the error:

Set Office 365 mailbox size limits using the below-listed cmdlet commands:

Steps For Single User for Office 365 Increase Mailbox Size Limits

  1. First, connect to Exchange Online using remote PowerShell.
  2. Now, run the following command to upgrade Office 365 Mailbox Size for a single user.
increase-single-user-mailbox-size using PowerShell

Note: The placeholder GUID, email address, or UPN of the mailbox user. Whereas, the placeholder represents numbers in MB, GB, and KB.

3. Next, you must check whether the current list of quotas is attached to the mailbox or not. To increase Office 365 mailbox size, execute the following command.


Steps For Multiple Users to Increase Mailbox Size in Office 365:

  1. Connect to the Exchange Online using the remote PowerShell.
  2. To set the mailbox size limits for all users in an organization, run the following command.

Note: You can also apply filters to the Get-User cmdlet or Get-Mailbox cmdlet to control the user for whom you have applied these changes.

Let’s execute this command in the Finance department of any organization.


The above method works wonders to deal with the Office 365 Mailbox Size Exceeded alert message. You should use these steps very carefully, as these are technical cmdlets scripts, and a minor error in the scripts can result in severe crucial data loss.

Hence It is always recommended to take a backup of your existing data in Office 365, just in case you mess up something then a copy of your entire mailbox would be ready with you.

Must Read: Office 365 Restore Email from Backup 

Office 365 Increase Mailbox Size – Benefits That You Should Know

  • Increased Office 365 mailbox size provides users with extra space for emails, attachments, and data, reducing storage concerns.
  • Enhanced organization and easier data management due to the expanded mailbox size.
  • Decreased risk of deleting important data with more available storage space.
  • Facilitates better collaboration among team members through sharing larger files and attachments.
  • It ultimately boosts productivity by allowing users to focus on work rather than managing mailbox storage.


In this blog, you have learned about how to increase Office 365 mailbox size in detail. I hope you will be able to resolve this issue after following the above-given methods.

To summarize, we provided you foolproof methods to help you solve the Office 365 mailbox size exceeded error. Follow the steps and do not forget to take a backup in case something goes wrong. Above mentioned software is a brilliant solution for creating a local backup of your existing data in Office 365.


By Ashwani Tiwari

I am an Expert Technical Analyst, specialized in assisting users with complex technological challenges. Through my blogs and articles, I offer expert guidance to help tackle these technical issues effectively. My true passion lies in providing valuable insights and simplifying complicated technicalities, enhancing user understanding and confidence.