What to do with public folders when moving to Exchange Online

Moving to Exchange online

Sometimes a migration to office 365 can be difficult when it comes to Public folders. When the plan is to migrate from for instance Exchange 2010 to office 365 Exchange Online a discussion must be made. What to do with the public folders? In my opinion there are 3 scenario’s that can be discussed. In this blog post i will write down these 3 scenario’s .

A little bit of history

For youngsters in IT like myself it is pretty hard to understand what public folders are and what they do. This comes because we never worked with them or have used them. Luckily there are lots of experienced Microsoft Professionals like my colleague Michel de Rooij.  Who can explain this perfectly.

So what is a public folder: According to TechTarget a public folder In Microsoft Outlook, a public folder is a folder created to share information with others. The owner of a public folder can set privileges so that only a select group of users have access to the folder, or the folder can be made available to everyone on the network who uses the same mail client. Public folders in Outlook can contain contacts, calendar items, messages, journal entries, or Outlook Forms.

What to do with Public Folder Scenario’s

In the scenario’s bellow i will write down 3 scenario’s what to do with public folders. In these options i will also keep notice that most companies want to get rid of their public folders.

Scenario 1: Migrate public folder to modern public folders

Microsoft has published a article on Technet on how to migrate legacy public folders to modern public folders on Office 365. In this case Microsoft just continues the support on public folders when they are migrated to Office 365.

The migration itself has some limitations which i will summarize bellow.

  • Exchange 2010 Sp3 or higher is needed
  • Legacy public folder cannot be larger the 2 GB
  • Public folder cannot contain \ or other strange symbols
  • Modern public folders are not accessible for legacy (on-premise) users
  • All users need to be migrated first
  • Max 1000 public folders allowed
  • Big bang migration with downtime

As you can see there are some limitations and difficulties. These difficulties are most of all in managing expectation at the business side cause public folders need to be cleaned or renamed.

Scenario 2: Migrate public folder to Office 365 groups

The second scenario is to migrate the legacy public folders to Office 365 groups. Microsoft has described this in the following Technet article. When moving public folders to Office 365 groups there are some difficulties that need to be managed first before you can start the migration.
One of these difficulties is that it is only possible to migrate the email and calendar items to an Office 365 group.

Bellow you find the summary of limitations.

  • All users must be migrated to Office 365 before you begin
  • Work process for end user will change ( they will use a office group instead of public folder)
  • Office 365 groups are not accessible for legacy users
  • Only mail and calendar items are supported
  • Maximum size of Public folder can be 25 GB to migrate
  • Phased migration is possible when using a > Exchange 2013 server
  • Downtime

Scenario 3: Do not migrate public folder to Office 365

When you have Exchange 2010 in a hybrid setup it is possible to configure the public folders co-existing. This means that the public folder stay where they are, but are accessible from on-premise and from online. There are some limitations, one of these limitations is that it is not possible to open this public folder from Outlook.office365.com/owa.

Remember i told you in the beginning that there is probably a scenario on how to get rid of the Public Folders? Well this is in my opinion the best and most business friendly way to do it.

Therefor just make sure the co-existing is in place. So next up you put the public folders in read only. and give the users a Shared mailbox, Office 365 group or even a team as their new place to collaborate from.

One last thing keep in mind that when you go for this option you have to keep your on-premise environment for a little bit longer before you decommission it.

Please follow and like us:

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.