Exchange Public folder and Shared mailbox migration

You may install the EdbMails application on multiple computers and migrate different public folders from different machines. During migration operation, you can select the required folders that you wish to migrate in parallel on respective computers.

When the growth of the public folder mailbox exceeds the size quota, Public folder mailbox growth in Exchange Online is managed using an auto-split feature that splits the public folder mailbox when it exceeds size quotas. This generates an error “Target public folder mailbox quota is exceeded”.

To resolve this issue, you need to wait for two weeks for the Office 365 auto-split feature to start. Automatic splitting will create a secondary mailbox for public folders and move some of the data from the primary mailbox to the secondary mailbox. It may not be possible to write any new data to your Office 365 public folders (this includes delivering emails to mailbox-enabled public folders), because the size quota has been reached. It is not possible to start the auto-split feature otherwise, or to manually redirect migration to additional public folder mailbox. The above is a standard Exchange Online behaviour.

It is strongly recommended that you use default storage quota to avoid problem. The settings on your target server should be the same

It is possible that when the size of a public folder mailbox is close to the limit, Microsoft may increase the mailbox storage size automatically.

You may also get the error described when you are migrating a public folder that exceeds the maximum folder size allowed in your target environment.

You need to change the quota settings of your target public folders. We recommend increasing the public folder quota to its maximum value, depending on your Office 365 plan. You can change the quota settings using PowerShell command.

Change the target quota limit to 100 GB, and the value when the warning message should be sent to 95 GB, by using the cmdlets below:

No, It is not possible. Exchange Server does not allow you to create the second public folder infrastructure in the same AD forest. Exchange Migration allows you to migrate public folders in a cross-forest migration scenario only.In addition, It is also not possible to migrate public folders in a hybrid environment because you cannot have public folders in both on-premises Exchange and Office 365 at the same time.