Office 365 Public Folders Migration: Why and when to use MigrationWiz and not the Microsoft native tool

Migrating legacy Microsoft Exchange Public Folders to Office 365 is a challenge that many Organizations are facing at the moment, and the first question that comes to mind is: “What tool shall I use?”

From my perspective and experience, you have two valid options to push your Public Folders to Exchange Online:

  1. The Microsoft Native tool
  2. MigrationWiz from BitTitan

Reasons to use the MigrationWiz Tool

When the source is a Hosted Exchange

Most of the steps you need to follow on the Microsoft TechNet article, to migrate the legacy public folders to Office 365, require full control on the source system. No Exchange hoster will give you the control and permissions you need to use the Microsoft Native tool, therefore using MigrationWiz will be the best option in this scenario.

When the source is Exchange 2013

Microsoft states the following, on the official technet article:

“Exchange supports moving your public folders to Office 365 and Exchange Online from the following legacy versions of Exchange Server:

  • Exchange 2010 SP3 RU8 or later
  • Exchange 2007 SP3 RU15 or later”

This means that when the source is Exchange 2013, at the moment there is no official and supported migration path to move the public folders to Office 365, as you can also read on the BitTitan’s blog article, that describes the experience of the Microsoft Exchange expert and blogger Todd Nelson.

Because you don´t need to patch your existing Exchange Servers

As described above, and stated by Microsoft, to run the native tool your source servers need to be patched with at least Exchange 2010 SP3 RU8 or Exchange 2007 RU15. Patching Exchange servers might require downtime, and if you´re moving to Office 365, chances are you will decommission all Exchange Servers, keeping only one for management if you are using AADSync. So why schedule a maintenance window and patch servers there are soon to be decommissioned? MigrationWiz supports major versions with no specific requirements on the service pack or update rollup.

Support for large Public folders

MigrationWiz adds great value, when you have large individual public folders, and/or the total amount of public folder data to be migrated is very large.

But let’s start with the individual public folders. Microsoft clearly states the following, on the native migration TechNet article:

“Before migration, if any public folder in your organization is greater than 2 GB, we recommend either deleting content from that folder or splitting it up into multiple public folders. If either of these options isn’t feasible, we recommend that you do not move your public folders to Office 365 and Exchange Online.”

Which means that they do not support the migration of public folders larger than 2GB, or at least if and when you have a problem with your migration (and believe me, chances are you will), related to folders bigger than 2GB, the Microsoft support will probably give you an answer based on the statement above.

By default the Public folders on Office 365 cannot be larger than 2GB, but as you can see on the Public Folder limits Technet article, that limit can be extended up to 10GB. If you have public folders with more than 2GB (and of course less than the 10GB limit), all MigrationWiz requires is that you prepare your target environment, by following this article.

Regarding the large total amount of data to migrate, the great value of the MigrationWiz tool, when compared to the native tool, is the capability of, in case of error, getting more detailed information, and more importantly, not having to restart a migration. I was forced to restart very big migrations, done with the Microsoft Native tool, after getting very vague errors, and because the Resume-PublicFolderMigrationRequest was not working, to get my failed migration back in motion. As you can imagine having to restart a 400GB Public folder migration that was 50% done, it´s not a good experience 🙂


As you can see on the example above, the errors on the MigrationWiz portal are very clear and detailed, which helps a lot when troubleshooting. Public Folder mailboxes in Office 365 have a limit of 50GB per mailbox, therefore, if you´re migrating more than 50GB of data you need to follow this MigrationWiz article.

More details and statistics during the migration

Although with the native tool, you can run a Get-PublicFolderMigrationRequestStatistics, with the “-includereport” option, and export it to csv, that is nothing compared to what the MigrationWiz portal provides you.


You can see both the total number and size, per item type, with errors or migrated successfully.


There’s also information on the data migrated, items migrated or transfer speed, for you to have a better understanding of how things are progressing and estimate total migration times.


You can see the migration history, and all kinds of statistics, including a very useful data and item speed per hour statistic.

All the above is, in my opinion and based on my experience, very important when you are migrating a large amount of data.

It´s easy to migrate

The way I see it, unless you have very good technical knowledge of both Exchange online and on-premises, you should go for a tool like MigrationWiz that makes your life much easier.

I’ve seen a lot of issues when using the Microsoft Native tool (and you can find some posts in my blog on how to solve them), and if you don’t have advance knowledge, and you want to use the tool, you should find someone that has that knowledge and experience, and can assist you with the migration.

To be clear:

Is the Microsoft native tool, to migrate public folders, a good tool? Yes!

Does it work? Yes!

Is it challenging from a technical perspective? Yes!

Reasons to use the Microsoft Native Tool

If none of the above is relevant to you or your Organization, and you are an expert on Exchange online and on-premises, then you can use the native tool.

The bottom line is that, everything I stated on this post is based on the large experience that I have with Office 365, and more specifically with migrating Public Folders to Exchange Online. I´ve helped dozens of Organizations to achieve that, and learned a lot in the process.

I hope this post was helpful and as always, let me know if you have questions!


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