Best Way to Increase Office 365 Mailbox Size to 100 GB

An Office 365 account has many benefits like all the account’s data and its details are fully secured and accessible globally. Any change in the document or spreadsheet is updated instantly and with the help of versioning, you can access the previous versions of the same file also. But like any other normal service, there are limitations in the services of the Office 365 account. The features are limited as per your Microsoft 365 subscription plan and you need to remind yourself that you should not exceed the given limitations. The current mailbox total size and its usage can be identified by visiting the mailbox usage section in the Office 365 Admin Center or the Exchange Online Admin Center.

The size of the various mailboxes is also limited and you get different kind of messages or notifications as you come near to the maximum capacity limit;

• Warning: The warning email is sent to the user when the mailbox is approaching the maximum size limit. The user should delete the non-critical emails as soon as he/she gets the warning email.
• Prohibit send: The user will get the prohibit-send email notification when the mailbox has reached the maximum size limit. In such a condition, you will not be able to send any new message to any other user.
• Prohibit send/receive: Office 365 will not allow any new incoming emails if the mailbox size limit is touched and it will send a non-delivery report (NDR) to the sender. To receive new emails, you should delete the non-critical emails from your inbox.

Here is the table that shows the total mailbox size limitation for each Office 365 plan;

Important factors about Office 365 Mailbox Storage

• The Office 365 user gets 100 GB of storage space in the archive mailbox. If the user enables an auto-expanding feature, then additional storage will be added when the archive mailbox touches 100 GB.
• To access the shared mailbox, the user should have an Exchange Online subscription. Without a license, the shared mailbox is limited to 50 GB. To increase the size limit, you should purchase the subscription with Exchange Online and the size of the shared mailbox will be 100 GB.
• The resource mailbox does not require a license to access it. But, its default size is 50 GB only. To increase the size, the user should purchase a subscription for Office 365 E3 or E5.

Increase Office 365 Mailbox Size to 100 GB Via PowerShell

All of us are using at least any one of such Office 365 plans and taking benefits of all these mailboxes. But if you exceed the given limitation, then you will have to delete the emails from the inbox to make space for new emails. If you do not want to delete your emails from the Office 365 mailbox storage or save it locally on the system drive, then you can choose the other option to increase the size of your mailbox using the Exchange Shell commands and following is the whole procedure of it;

1. Start the Windows PowerShell as an administrator (select Windows PowerShell application icon, right-click and select Run as administrator option) and run the following command;
   $UserCredential = Get-Credential

   The command will open the credentials request dialog box where you need to input the credentials of the Office 365 account.

2. You need to create a new session of the Exchange Online and you can complete it by running the below command;
   $Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $UserCredential -Authentication Basic -AllowRedirection
3. Now import the Exchange Online cmdlets for the local session using the below command;
   Import-PSSession $Session -DisableNameChecking
4. To get the current mailbox size limits, follow this command.
   Get-Mailbox < User ID > | Select *quota
5. Now to increase the mailbox size quota to 100 GB, you need to run the command;
   Set-Mailbox < UserID > -ProhibitSendQuota < Value > -ProhibitSendReceiveQuota < Value > -IssueWarningQuota <Value>

   Here is an example of the command-

   Set-Mailbox charlie@yourmail.com -ProhibitSendQuota 99GB -ProhibitSendReceiveQuota 98GB -IssueWarningQuota 98GB

   Here you have fixed the increased storing warning quota at 98 GB and send quota at the 99 GB so that you will have 100 GB storage in your mailbox.
   If you want to apply the changes to multiple users, then you can run a different command based on a criterion.

   Get-User | where {$_.Team -eq “Developer”} | Get-Mailbox | Set-Mailbox -ProhibitSendQuota 99GB -ProhibitSendReceiveQuota 98GB -IssueWarningQuota 98 GB

   Here, you have increased the mailbox size of the whole team of the developers till 100 GB.
   NOTE: In order to make changes to the multiple accounts, you should have the Administrator privileges to apply the desired changes.

6. To set mailbox size limits on all the users within the organization, use this command.
   Get-Mailbox | Set-Mailbox -ProhibitSendQuota < Value > -ProhibitSendReceiveQuota < Value > -IssueWarningQuota < Value >
7. After making all the changes, you can choose to the end the session;
   Remove-PSSession $Session

Conclusion

The above method is quite easy to follow if you have basic technical knowledge to run commands in the Windows PowerShell and you can increase the size limitation of a single or multiple Office 365 accounts, but you should keep in mind that increasing the mailbox size will not affect the other limitations like a number of mailbox folders, address book limits, retention limits, distribution group limits, moderation limits, receiving and sending limits, reporting and message trace limits, etc. So, first take Microsoft 365 backup when you are going to increase the mailbox size, then you should also check that what are the other limitations that you need to increase for optimal usage of the increase mailbox storage size.