PST migration to office 365 [Import PST to Office 365 Mailbox]

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Sunil Chauhan
Expertise in Microsoft Exchange Server, Office 365, and PowerShell scripting, In my spare time I love writing tech blogs and taking photos.
In this article, I will demonstrate that how to do a PST migration from Exchange Server to Office 365. This method allows importing one single PST, or multiple PST's at once.

In my previous post link here, I showed how to export a PST from an office 365 mailbox using the EOP portal, in this post, I will cover how can we do bulk PST migration for multiple users or import the PST into an Exchange Online Mailbox.

NOTE: You will need to have "Import Export role" assigned to your admin account be able to perform this action.

The process is pretty simple and straightforward but requires some preparation. I will explain the process step by step.

1st step: Export-Mailbox data to PST file which you wish to migrate to office365.  (One thing to keep in mind is before you start a mailbox export, set forwarding on the mailbox so that any new emails will get delivered to new mailbox)

2nd step: Upload all the data to the Cloud.

Let's walk through the step - first sign in to EOP (Exchange Online Protection Portal)

Under "Data governance" Click on Import Option.

On the next screen, click on "New Import Job".

This will bring up options to create a new Import Job.

Here, Provide a Job Name of your choice.

Note: Job name has few limitation please make sure you meet the following "2-64 lowercase letters, numbers, hyphens, and underscores, must start with a letter and no spaces"

Next screen will bring up options for data import, Select Upload your data, and click Next.

Next, you will come across the Import Data instructions.

In 1 step, you will be presented a link to detailed instruction guide, find the link here.

2nd step, you need to click on "Show network Upload SAS Url"  Click this link to get the "Network Update Url", once you see the URL, make a copy of it somewhere.

3rd step, before you can upload the PSTs, you'll need to install the Azure AzCopy Tool, Download the tool from the link given in the Import Data instructions and install it on the system where you have access to the PST files you want to upload.

Once the Azure AzCopy Tool is installed, we are ready to upload.

Next, Open the command prompt and run the command in below format to initiate the PST files upload.

For Example: AzCopy.exe /Source:\\FileServer\PSTs /Dest:<SAS URL>  /V:"c:\PstImportLogs\log.log"

Below is a Sample SAS URL (Taken from Technet article)


Next, your PST Upload will begin and you will be able to see the progress of PST files uploading.  Wait for the PST file(s) to finish uploading. Note that it may take several hours to complete depending on the size of the data file(s).

Note: If you wish to review the PST file in SAS storage location, you can check the uploaded files using the  Microsoft Azure Storage Explorer tool (for detailed instructions visit here)

Next, Once the PST file import completes, we need to select the check boxes "I am finishing uploading my files"  and "I have access to the Mapping File".

The next screen will bring up the CSV file import section.  We need to set up the CSV file in the format shown below. You can download a sample csv format file from here

Workload,FilePath,Name,Mailbox,IsArchive,TargetRootFolder,ContentCodePage,SPFileContainer,SPManifestContainer,SPSiteUrl Exchange,,testuser.pst,testuser@contoso.onmicrosoft.com,FALSE,/,,,,

Next, upload the CSV file and click on Validate to check for any errors.

If its successful click on the save.

After that, you will see the Success Screen and can close the wizard.

Now the Analysis process will begin. Once the Analysis finishes, you will be able to click on the

"Import to Office 365" button.

This will bring you two options:

Do you want to filter your data?

a) Yes, I want to filter it before importing. (select only if you don't want to import everything)

b) No, I want to import everything. (select for importing everything)

Select the 2nd radio button and click on "Next" to import everything.

On next screen click "Import Data", that should complete the import request with a "Success!" Message.

You can further monitor the progress of each PST import and can also Delete the Job From here.

This completes the PST import request, now you can monitor the mailbox statistics and you should see the increased number of items in the mailbox.

To Summarize

In this post, I have explained how we can do a bulk PST migration or single user PST Import to a Mailbox hosted in the office 365.


I hope you found this post helpful and informative. Please feel free to leave your comments and feedback.


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