How do I migrate large mail items to Office 365?
Answer:
Important: The steps in this article require that you connect to Office 365 with Windows PowerShell. Refer to the Connect to Office 365 PowerShell article from Microsoft for detailed steps on how to connect to Office 365 using Windows PowerShell.
To migrate items to Office 365 that are larger than the EWS defaults, you will need to run the following PowerShell scripts.
First, you should run this script against your Office 365 environment to determine what your current settings are:
Get-Mailbox testuser01 | fl mailboxplan,maxsendsize,maxreceivesize
Notes:
- The user can be any standard user on Office 365 that has an Office 365 license assigned that contains a mailbox license.
- It should be a user whose settings have not been previously modified.
Example results:
MailboxPlan: ExchangeOnlineEnterprise-4b910ff9-8b91-4f2e-960c-302a90c95668
MaxSendSize: 35 MB (36,700,160 bytes)
MaxReceiveSize: 36 MB (37,748,736 bytes)
Next, run this script against your Office 365 environment to set the Mailbox Plan, the Max Send Size and the Max Receive Size:
Get-MailboxPlan | Set-MailboxPlan -MaxSendSize 150MB -MaxReceiveSize 150MB
Note: New users created after you change the mailbox plan will have 150MB as the max send and receive size. However, the current user will still have 35MB. To increase the limit for all users you can run:
Get-Mailbox | Set-Mailbox -MaxReceiveSize 150MB -MaxSendSize 150MB
The example below shows how you can validate that the new limits are applied:
PS C:\Windows\system32> Get-Mailbox testuser01 | fl mailboxplan,maxsendsize,maxreceivesize
MailboxPlan: ExchangeOnlineEnterprise-4e910ff9-8b91-4f2e-960c-302a90c65668
MaxSendSize: 150 MB (157,286,400 bytes)
MaxReceiveSize: 150 MB (157,286,400 bytes)
Comments
8 comments
You can change the default for an organization by adjusting the default message size restriction. In the Exchange admin center Simply select recipients > mailboxes then click “. . .” and select Set default message size restrictions.
You can then specify the maximum message size for new mailboxes (only for those you create in the future).
For existing users...
To edit multiple mailboxes select recipients > mailboxes and select multiple mailboxes. Then from the Bulk Edit pane under Message Size Restrictions select Update.
You can customize a single mailbox by selecting recipients > mailboxes and then select a user’s mailbox. Click the edit icon , then under Message Size Restrictions, click View details and then specify the maximum message size.
Credit due to: https://blogs.office.com/en-us/2015/04/15/office-365-now-supports-larger-email-messages-up-to-150-mb/
After following the guide - "Connect to Office 365 PowerShell" from Microsoft listed in this KB article, you need to follow additional guide - "Connect to Exchange Online PowerShell" to be able to execute those PS commands, otherwise you will get errors from PowerShell such as "The term 'Get-Mailbox' is not recognized as the name of a cmdlet, function, script file, or operable".
Life saver Georgiy Frolov !
Gregoriy FTW.
Thank you.
MaxSendSize: 150 MB (36,700,160 bytes)
MaxReceiveSize: 150 MB (37,748,736 bytes)
Those numbers don't match up.
Also, it seems like this does not modify existing mailboxes, only new ones created with that plan/policy.
https://docs.microsoft.com/en-us/powershell/module/exchange/mailboxes/set-mailboxplan?view=exchange-ps
Modifying the settings in a mailbox plan doesn't affect existing mailboxes that were created using the mailbox plan. The only way to use a mailbox plan to modify the settings on an existing mailbox is to assign a different license to the user, which will apply the corresponding mailbox plan to the mailbox.
I will have the KB updated so it shows the correct numbers:
MaxSendSize : 150 MB (157,286,400 bytes)
MaxReceiveSize : 150 MB (157,286,400 bytes)
You are correct, the command "Get-MailboxPlan | Set-MailboxPlan -MaxSendSize 150MB -MaxReceiveSize 150MB" does not modify mailboxes that already exist.
The next command will modify the max size for all existing mailboxes: "Get-Mailbox | Set-Mailbox -MaxReceiveSize 150MB -MaxSendSize 150MB"
From Frovlov
"After following the guide - "Connect to Office 365 PowerShell" from Microsoft listed in this KB article, you need to follow additional guide - "Connect to Exchange Online PowerShell" to be able to execute those PS commands, otherwise you will get errors from PowerShell such as "The term 'Get-Mailbox' is not recognized as the name of a cmdlet, function, script file, or operable".
Actually you don't even need to follow the Connect to Office 365 PowerSehll guide you just need to do the Connect to Exchange Online Power Shell link and follow those directions to get this done. Also don't really need the first command as its just to check the current size and also can be used after to verify results as well.
I'd recommend updating these steps to address connecting to Exchange Online when multi-factor authentication is enabled. Microsoft has instructions online.
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