The process of migrating Public Folders is a complicated one unfortunately. Luckily, if you are migrating from Exchange 2013 or Exchange 2016 then Microsoft has made things a bit easier for you, this is still going to be a bit of a slog to complete, but much less so than migrating from legacy versions of Exchange.
Before we get onto the Migration we need to ensure that we hit the following migration prerequisites:
- Exchange Version:
Exchange 2013 CU15 or Higher
Exchange 2016 CU4 or Higher
- Exchange Online Permissions:
Must be a member of the organisation management role group
- Local Exchange Permissions:
Organization or Server Management RBAC Group
- No Single Public folder larger than 25GB. If you have public folders that are larger than this you should consider deleting some content or splitting it up into multiple folders
- MRS Proxy service running on one of your local Exchange Servers
Overview
The migration process can be broken down into the following steps:
- Download the Migration Scripts
- Prepare your local server
- Prepare Exchange Online
- Create Migration files
- Create public folder mailboxes
- Start the migration
- Lock access to the old public folders
- Finish the Migration (Switchover to Exchange Online)
- Test
- Complete the Migration
Download the Migration Scripts
Download all of the following scripts - https://www.microsoft.com/en-us/download/details.aspx?id=54855
I would recommend that you save them all in a folder called C:\PFScripts to make following this article easier.
Prepare the Local Exchange Server
Only the following versions of Exchange server are supported by these scripts
- Add your onmicrosoft domain to your local server
New-AcceptedDomain -Name PublicFolderDestination_MigrationPF -DomainName "example.mail.onmicrosoft.com" -DomainType InternalRelay
- We need to rename any public folders whose name contains a backslash '\'
Get-PublicFolder -Recurse -ResultSize Unlimited | Where {$_.Name -like "*\*" -or $_.Name -like "*/*"} | Format-List Name, Identity, EntryId
- If this comes back with any results simply rename the public folder without the backslash.
- Now we need to check for the existence of any previous successful or failed migration attempts.
Get-OrganizationConfig | Format-List PublicFoldersLockedforMigration,
PublicFolderMigrationComplete,
PublicFolderMailboxesLockedForNewConnections,
PublicFolderMailboxesMigrationComplete
- If this command returns $true for any of the options then you need to run this to reset them
Set-OrganizationConfig -PublicFoldersLockedforMigration:$false -
PublicFolderMigrationComplete:$false -
PublicFolderMailboxesLockedForNewConnections:$false -
PublicFolderMailboxesMigrationComplete:$false
- Let’s take a snapshot of the existing structure so we can verify the success of the migration afterwards
Get-PublicFolder -Recurse -ResultSize Unlimited | Export-CliXML OnPrem_PFStructure.xml
Get-PublicFolderStatistics -ResultSize Unlimited | Export-CliXML OnPrem_PFStatistics.xml
Get-PublicFolder -Recurse -ResultSize Unlimited | Get-PublicFolderClientPermission | Select-Object Identity,User -ExpandProperty AccessRights | Export-CliXML OnPrem_PFPerms.xml
Get-MailPublicFolder -ResultSize Unlimited | Export-CliXML OnPrem_MEPF.xml
- Put all the files generated above in the C:\PFMigration folder
Prepare Exchange Online
Open an Exchange Online Shell, connect to Exchange Online and then do the following:
- We need check that there are no existing migration requests
Get-PublicFolderMigrationRequest | Get-PublicFolderMigrationRequestStatistics
Get-MigrationBatch | ?{$_.MigrationType.ToString() -eq "PublicFolder"}
If either of these commands returns anything, delete the existing requests
- We need to check that PAW is enabled
- Get-MigrationConfig
- Look under the features heading
- If you see can see PAW listed then carry on, if it is not enabled you will likely need to speak to office 365 support.
- In the Exchange Online EAC check that there are no existing public folder mailboxes, if there are delete them.
Generate the Migration Files
Open Exchange PowerShell on your local Exchange server, change the directory to C:\PFScripts run the following commands
.\Export-ModernPublicFolderStatistics.ps1 PublicFolderstats.csv
.\ModernPublicFolderToMailboxMapGenerator.ps1 -MailboxSize 25GB -MailboxRecoverableItemSize 1GB -ImportFile .\publicfolderstats.csv -ExportFile C:\PFMigration\map.csv
If you’ve previously done Exchange 2007 or 2010 Public folder migrations you’ll be relieved to learn you only need to generate these 2 files.
Create Public Folder Mailboxes
In Exchange Online, mailboxes act as the backbone for the Public Folder storage, we need to create these mailboxes before we can create public folders. Connect to Exchange Online PowerShell and run this script:
$mappings = Import-Csv C:\PFMigration\map.csv
$primaryMailboxName = ($mappings | Where-Object FolderPath -eq "\" ).TargetMailbox
New-Mailbox -HoldForMigration:$true -PublicFolder -IsExcludedFromServingHierarchy:$false
$primaryMailboxName
($mappings | Where-Object TargetMailbox -ne $primaryMailboxName).TargetMailbox | Sort-
Object -unique | ForEach-Object { New-Mailbox -PublicFolder
-IsExcludedFromServingHierarchy:$false $_ }
Start the migration
It’s time to get the migration started! From your Local Exchange Server open Exchange Shell, change directory to C:\PFscripts and run the following command
.\Sync-ModernMailPublicFolders.ps1 -Credential (Get-Credential) -CsvSummaryFile:sync_summary.csv
When prompted enter the login details for your Exchange Online admin account.
Now switch to Exchange Online PowerShell and do the following,
$Source_Credential = Get-Credential domain\exchangeadmin
(replacing the domain \ user name with your own)
$Source_RemoteServer = "server.domain.com"
(replacing the server name with the name of your MRS Proxy Server)
- Run this Script
PfEndpoint = New-MigrationEndpoint -PublicFolder -Name PublicFolderEndpoint
-RemoteServer $Source_RemoteServer -Credentials $Source_Credential
[byte[]]$bytes = Get-Content -Encoding Byte C:\PFMigration\map.csv
New-MigrationBatch -Name PublicFolderMigration -CSVData $bytes -SourceEndpoint
$PfEndpoint.Identity -NotificationEmails email@domain.com
- Start the Migration
Start-MigrationBatch PublicFolderMigration
Lock access to the old public folders
Now, we need to stop people who are using the existing on premise public folders from being able to access them. To do this open Exchange Shell on any of your Exchange servers
Set-OrganizationConfig -PublicFolderMailboxesLockedForNewConnections $true
This can take up to 2 hours to replicate around and take effect for all users.
Finish the Migration
Connect to Exchange Online PowerShell and run this command
Complete-MigrationBatch PublicFolderMigration
Test
Before unlocking the new public folders for all users, I would recommend testing that the migration has completed successfully. To do this, assign yourself or some test users access to the new public folders
Set-Mailbox -Identity
-DefaultPublicFolderMailbox Once you have confirmed everything looks ok you can unlock the public folders for all users
Set-OrganizationConfig -RemotePublicFolderMailboxes $Null -PublicFoldersEnabled Local
Complete the Migration
Finally, run the following two commands on your local Exchange server
.\SetMailPublicFolderExternalAddress.ps1 -ExecutionSummaryFile:mepf_summary.csv
Set-OrganizationConfig -PublicFolderMailboxesMigrationComplete:$true -PublicFoldersEnabled Remote
And that’s it, you are finally done! If you are looking for an easier route to migrating Public Folders to Office 365 consider trying.
And that’s it, you are finally done! If you are looking for an easier route to migrating Public Folders to Office 365, then consider trying Kernel for Exchange Server Recovery tool to efficiently recover your lost Exchange database and convert EDB to PST, Live Exchange and Exchange Online within the same cycle. It also provides smart backup restoration facility, live mailbox preview feature, and easy approach to migrate public folders from live Exchange to Exchange online.
