Have you reached your Office 365 mailbox size limit and want to know how to increase it? Then we first have to check if you can increase the mailbox within your current Office 365 plan.
Depending on your Microsoft Office 365 plan you can have either a 50GB or a 100GB mailbox size as you can see in the table below.
If you have reached the limit within your plan, then we still have two options. We can either move the mail to the Online Archive or in some cases switch over to a different Office 365 subscription.
| Microsoft Office 365 Plan | Exchange Online Plan | Mailbox size | Online Archive size |
|---|---|---|---|
| Microsoft 365 Business Basic | Plan 1 | 50GB | 50GB |
| Microsoft 365 Business Standard | Plan 1 | 50GB | 50GB |
| Microsoft 365 Business Premium | Plan 1 | 50GB | 50GB |
| Office 365 F1 | Kiosk | 2GB | Add-on |
| Office 365 E1 | Plan 1 | 50GB | 50GB |
| Office 365 E3 | Plan 2 | 100GB | Unlimited |
| Office 365 E5 | Plan 2 | 100GB | Unlimited |
| Microsoft 365 F3 | Kiosk | 2GB | Add-on |
| Microsoft 365 E3 | Plan 1 | 50GB | Unlimited |
| Microsoft 365 E5 | Plan 1 | 50GB | Unlimited |
Microsoft has increased in the mailbox limitation in the past, in 2013 and later again for the E3 and E5 plans. So if your mailboxes were created before 2016 then it’s possible that your mailboxes still have the old limits, 25Gb instead of 50Gb for Exchange Online plan 1 and 50Gb instead of 100Gb for plan 2.
Also when you have upgraded your Office 365 plan to E3, for example, then the mailboxes may still have the old mailbox size limit.
You can check the current mailbox size of a user in the Exchange Admin Center.
Or with PowerShell
1. <font style="vertical-align: inherit;"><font style="vertical-align: inherit;"># Conectarse a Exchange Online</font></font><font></font> 2. Connect-Exchangeonline -userprincipalname admin@contoso.com<font></font> 3. <font></font> 4. # Get the mailbox size limits<font></font> 5. Get-Mailbox -identity johndoe@contoso.com | select IssueWarningQuota, ProhibitSendQuota, ProhibitSendReceiveQuota<font></font> 6. <font></font> 7. # Get all mailbox sizes<font></font> 8. Get-Mailbox | select DisplayName, IssueWarningQuota, ProhibitSendQuota, ProhibitSendReceiveQuota
Increase Mailbox size Office 365 with PowerShell
Increasing the mailbox size can only be done with PowerShell. You will need to have the Exchange Online Module installed before you can connect to Exchange Online with PowerShell.
We need to set 3 values:
- IssueWarningQuota – When the warning is displayed in Outlook
- ProhibitSendQuota – Determines when the user can’t send mail anymore
- ProhibitSendReceiveQuota – The user can’t send or receive mail when reached
You want to give the user a warning on time, not when the mailbox limit is reached. So we set the warning to 95Gb. Then prohibit the sending of new mail at 98Gb, so we still have a little room to receive mail until we reach the limit of 100Gb.
1. # Connect to Exchange Online<font></font> 2. connect-exchangeonline -userprincipalname admin@contoso.com<font></font> 3. <font></font> 4. # Increase mailbox size<font></font> 5. Set-Mailbox -identity johndoe@contoso.com -IssueWarningQuota 95GB -ProhibitSendQuota 98GB -ProhibitSendReceiveQuota 99GB
You can also increase all the mailboxes in one command. If all your users have the same licenses then you can simply run the following PowerShell command to increase mailbox size to 100Gb in Office 365.
1. Get-Mailbox | Set-Mailbox -identity johndoe@contoso.com -IssueWarningQuota 95GB -ProhibitSendQuota 98GB -ProhibitSendReceiveQuota 99GB
If you have a large tenant with different Microsoft Office 365 plans for your users then you can’t increase all the mailboxes. You could run the command above, but it will throw a lot of errors for all the mailboxes that can’t be changed.
With the command below we get all the user mailboxes (not the shared) and select the mailboxes that have a ProhibitSendReceiveQuota of 50GB. Also, we need to make sure that the user has an Exchange Online Plan 2 mailbox, which we do with BPOS_S_Enterprise. (BPOS_S_Standard is EO Plan 1)
1. Get-mailbox -Filter {RecipientTypeDetails -eq "UserMailbox"} | <font></font>
2. Where-Object {($_.ProhibitSendReceiveQuota -eq '50 GB (53,687,091,200 bytes)') -and ($_.PersistedCapabilities -contains "BPOS_S_Enterprise")} | <font></font>
3. Set-mailbox -ProhibitSendQuota 98GB -ProhibitSendReceiveQuota 99GB -IssueWarningQuota 95GB
Enable Office 365 Online Archive
If you have reached the limits of your Office 365 plan then your only option is to start moving the mail older than 2 years to the Online Archive.
We first have to check if the archive is enabled in the Exchange Admin Center. If you open the mailboxes you will see a column with the Archive Status. If the Archive Status is none then we can enable it.
- Select the user
- Click on Manage mailbox archive
- Enable the archive.
We can also use PowerShell to enable the Office 365 Online Archive
1. # Connect to Exchange Online<font></font> 2. connect-exchangeonline -userprincipalname admin@contoso.com<font></font> 3. <font></font> 4. # Enable the mailbox for John Doe<font></font> 5. Get-mailbox -Identity johndoe@contoso.com | Enable-Mailbox -Archive
If you want to enable the archive for all users then use the following PowerShell cmd:
1. # Connect to Exchange Online<font></font>
2. connect-exchangeonline -userprincipalname admin@contoso.com<font></font>
3. <font></font>
4. # Enable the Online Archive for all mailboxes<font></font>
5. Get-mailbox -Filter {ArchiveStatus -eq 'none' -and RecipientTypeDetails -eq "UserMailbox"} | Enable-Mailbox -Archive
Retention Tag Policies
We can use retention tag policies (RTP) to move the mail automatically to the archive. By default, there should be an RTP that archives all the mail older then 2 years to the archive.
In the old Exchange Admin Center, select compliance management > retention tags. There should be a “Default 2-year move to archive” policy that moves the mail to the archive after 730 days (2 years).
Retention Tags are assigned to a Retention Policy, which is again assigned to a mailbox. The default retention policy is always assigned to a mailbox if no other policy is assigned.
Frequently Asked Questions
What is the Exchange Online plan 1 mailbox size
The Exchange Online Plan 1 mailbox is 50GB and the size of the online archive is also 50Gb
What is the Exchange Online plan 2 mailbox size
The Exchange Online Plan 2 mailbox is 100GB and the size of the online archive is unlimited
What is the Exchange Online Kiosk mailbox size
Kiosk mailboxes are only 2GB and don’t come with an online archive. It’s possible to buy the online-archive as an add-on.
Can you increase the Office 365 mailbox size over 100gb
No, you will have to use the online archive for this.
Wrapping Up
Increasing the mailbox size in Office 365 only solves the problem temporarily (or for a couple of years). At the moment you can’t go beyond the 100GB for a mailbox, so make sure you have the archive mailboxes enabled and retention policies the move the mail after 2 years to the archive.
Another good way to limit the growth of the mailboxes is to train your users to share links to documents instead of attaching the document.
If you have any questions, just drop a comment below.
You may also like the following article:
- Best Practice to Secure Office 365