If your on-premises messaging system is Microsoft Exchange, POP access to mailboxes isn't enabled by default. To enable POP access to mailboxes in an Exchange organization, see the following topics:

• Exchange 2007: Verify that Your Exchange Environment is Configured to Support POP3 and IMAP4
  
• Exchange 2003: How to Enable a POP3, IMAP4, or NNTP Virtual Server
  

To create a service account that can access all mailboxes in an Exchange organization, see the following topics:

• Exchange 2007 Permissions: Frequently Asked Questions: "I have a third-party messaging application that requires full access to each user's mailbox."
  
• Microsoft Knowledge Base article 821897, "How to assign service account access to all mailboxes in Exchange Server 2003"
  

To add POP subscriptions to many accounts at one time, you have to correlate the existing mailboxes in the on-premises messaging system and the existing mailboxes in Outlook Live by using a CSV file. The CSV file is in the following format:

RemoteAlias,OutlookLiveAlias
User1,NewUser1
User2,NewUser2
User3,NewUser3

Note   Don't modify the variable names in the first row. They're used in the Windows PowerShell code in the next step.

The RemoteAlias value is the alias on the left side of the @ symbol for the user's e-mail address in the on-premises messaging system. For example, if the e-mail address is akohl@contoso.edu, the value of RemoteAlias is akohl. The OutlookLiveAlias value is the alias on the left side of the @ symbol for the user's e-mail address in Outlook Live. The values of RemoteAlias and OutlookLiveAlias for a user may be the same.

If you have an existing on-premises directory service, you can use a directory export tool to export the account data from your existing directory service to a CSV file. For information about how to use the Csvde tool in Windows Server 2003 to export data from the Active Directory directory service or from the Active Directory Application Mode (ADAM) directory service, see CSVDE.

To export the account data from Outlook Live, you can run the following command after you have connected to the Outlook Live server-side runspace:

Get-Mailbox | Format-List Name,PrimarySmtpAddress,Alias -Wrap > <file path>\OutlookLive.txt

On a local computer that has Windows PowerShell installed and configured, perform the following steps:

1. Copy the following code snippet.
   
   #Begin custom variables
   $filePath = "C:\My Documents\StudentList.csv"
   $outlookLiveAliasOrg = "live.contoso.edu"
   $remoteOrg = "corp.contoso.edu"
   $serviceAccount = "corp\serviceaccount"
   $password = 'Pa$$word1'
   $popIncomingServer = "pop.corp.contoso.edu"
   $popIncomingAuth = "Basic"
   $popIncomingPort = "995"
   $popIncomingSecurity = "SSL"
   $popLeaveOnserver = $false
   #End custom variables
   
   $securePassword = (ConvertTo-SecureString -String $password -AsPlainText -Force)
   $students = Import-Csv $filePath
   
   if ($students -ne $null)
   {
   foreach($student in $students)
   {
   $subscriptionName = $student.RemoteAlias.Trim() + " Edu Subscription"
   $emailAddress = $student.RemoteAlias.Trim() + "@" + $remoteOrg
   $mailbox = $student.OutlookLiveAlias.Trim() + "@" + $outlookLiveAliasOrg
   $IncomingUserName = $serviceAccount + "\" + $student.RemoteAlias
   
   write-output ([string]::Concat("Creating Subscription: ", $subscriptionName," ", $emailAddress, " ", $mailbox))
   New-PopSubscription -Name $subscriptionName -IncomingUserName $IncomingUserName -IncomingPassword $securePassword -IncomingServer $popIncomingServer -EmailAddress $emailAddress -Mailbox $mailbox -IncomingAuth $popIncomingAuth -IncomingPort $popIncomingPort -IncomingSecurity $popIncomingSecurity -LeaveOnServer $popLeaveOnserver
   }
   }

2. Paste the copied code snippet in Notepad or another text editor.
   
3. Save the text file with a descriptive name and the .ps1 file extension, for example, POPMigration.ps1.
   

You have to customize the variables in the script to match the values required for your organization. The variables are described in the following table.

Note   Be sure to leave the existing quotation marks when you replace the example values with the correct values for your organization.

After you customize the script, connect to the Outlook Live server-side runspace and run the script:

<script file name and path>

For example, if you saved the script named "C:\My Documents\POPMigration.ps1", run the following command:

"C:\My Documents\POPMigration.ps1"

Users can log in to their on-premises mailboxes to verify that e-mail messages in their Inboxes were successfully imported. If you set the $popLeaveOnServer variable to $false, their on-premises Inbox should be empty.

A user can also check the status of the POP subscriptions in their Outlook Live mail by clicking Options > Account > Other Accounts. If you created the POP subscription using the script in this topic, the account name is "<user alias> Edu Subscription".

For more information, see FAQs: Downloading E-Mail from Connected Accounts.

As long as a POP subscription exists, Outlook Live will poll the on-premises mailbox at regular intervals to retrieve new e-mail messages. The polling interval may be anywhere between 15 minutes and one hour.

If you are going to remove the migrated mailboxes from the on-premises messaging system, you should remove the POP subscriptions from the corresponding Outlook Live mailboxes. Removing the POP subscription doesn't remove any e-mail messages from the Outlook Live mailbox.

Remove-Subscription <subscription name> -Mailbox domain\alias

Remove-Subscription "akohl Edu Subscription" -Mailbox live.contoso.edu\akohl

RemoteAlias,OutlookLiveAlias
User1,NewUser1
User2,NewUser2
User3,NewUser3