1. Import PST Files into Microsoft 365: The Ultimate Comprehensive Guide

How to Import PST Files into Microsoft 365: Step-by-Step Guide

Importing PST files into Office 365 seems complicated. However, you’ll have everything up and running smoothly with this easy-to-follow guide.

Preparing the Archive Mailbox:

Assign necessary licenses & Enable archive Mailbox:

1. Assign the Mailbox Import Export Role

To import PST files, you first need permission. Without it, you won’t be able to complete the process. Follow these steps to assign the correct role:

1. Sign in to Exchange Admin Center.
2. Expand Roles and click on Admin roles.
3. Select Organization Management.
4. Click on the tab Permissions.
5. Select Mailbox Import Export role.
6. Click Save.

Key Point: The change takes up to 24 hours to take effect. However, in most cases, it will be active within 1 hour. You can verify your permissions later by trying to access the Import section. If you don’t have access, the role not have been applied yet.

2. Create a New PST Import Job

Once you have the necessary permissions, you can create an import job. Here’s how:

1. Sign in to Microsoft Purview compliance portal.
2. Expand Data lifecycle management and click on Microsoft 365.
3. Choose Import.
4. Click on New Import Job.
5. Click on + New import job. Give your job a clear and descriptive name (e.g., “PST Import-Department”).
6. You can follow the on-screen instructions to set up the job. Microsoft 365 will guide you through the initial process. It will ask you if you want to upload the PST files.

Note: We have enabled the above-highlighted notification in Assign the Mailbox Import Export Role 

Note: 
Copy the SAS URL to your clipboard. It will be useful for viewing the uploaded PST in Microsoft Storage Explorer. Do not close the current SAS URL window. Otherwise, you will need to generate another SAS URL to upload the PST to the blob storage. There is no limitation on creating SAS URLs.

An SAS URL is a secure HTTPS connection. It ensures the safety of our data. This is important when uploading files directly to Azure blob storage.

3. Upload Your PST Files to Microsoft 365’s Azure Storage

Microsoft 365 uses Azure Storage to hold your PST files before importing them into mailboxes. Here’s how to upload your files to Azure:

1. Download AZ Copy (Microsoft) and place it in the folder.
   • https://learn.microsoft.com/en-us/azure/storage/common/storage-use-azcopy-v10?tabs=dnf
2. Use the source directory on the shared drive \\SERVER\PST or local drive (D:\PST).
3. Start Command Prompt as an administrator.
4. Change the directory to C:\Temp.
5. Paste the SAS URL you copied in the previous step into the command.
6. Run the command to copy the PST file to Azure.

TIP: 
If your PST files are located in D:\PST_Files and the SAS URL provided by Microsoft 365 is https://example.sasurl.com, your command would look like this: 

azcopy.exe copy "<Source location of PST files>" "<SAS URL>"

Note: 
In the article, I used a network share as an example. I encountered a minor issue while running the command. You need to add the --recursive option, as recommended by Microsoft.

You can use network share or local drive to upload your PST to Azure Blob Storage.

Tip: Always check the log file after the upload is finished to ensure there were no errors.

4. Verify the PST Files Have Been Uploaded Successfully

Once your files are uploaded, you can confirm the upload status:

1. Download and install the Azure Storage Explorer – cloud storage management | Microsoft Azure
2. Launch Microsoft Azure Storage Explorer.
3. Right-click on Storage Accounts.
4. Select Connect to Azure Storage.
5. Choose Blob container.
6. Enter a Display name.
7. Paste the Blob container SAS URL obtained from the previous step.
8. Click Connect.
9. The PSTs folder and the PST file will now be visible.

Note: I successfully connected to the blob storage using the SAS URL. Since I have not uploaded any PST files to the blob storage yet, it is currently showing as data unavailable.

Tip:
Azure Storage Explorer cannot be used to upload or modify PST files. The only supported method for importing PST files is via AzCopy. Additionally, you cannot delete PST files once they are uploaded to the Azure blob. Attempting to delete a PST file will result in a permissions error.

If the files are not listed immediately, give it some time to refresh. You can also manually refresh the page to speed up the process.

5. Create a PST Import Mapping File

The PST mapping file tells Microsoft 365 which mailbox each PST file should be imported into and where. Here’s how to set it up:

1. Download a copy of the PST import mapping file from either the direct link or Microsoft.
2. Open Microsoft Excel.
3. Navigate to the advanced options in Excel and make the following changes:
   • Uncheck the “Use system separators” option.
   • Set the Decimal separator to a period (.)
   • Set the Thousands separator to a comma (,)
4. Open the CSV file with Microsoft Excel and edit the values.
5. You can open the CSV file with Notepad to edit the values. You can also verify that it is saved as a comma-delimited file.
6. Microsoft Recommendation Mapping PST,
   • FilePath: The path to your PST file in Azure. This is provided in the Import job after uploading the files.
   • Mailbox: The email address of the Office 365 mailbox where the PST should be imported.
   • IsArchive: Set this to TRUE if you want the PST imported into the mailbox’s archive. Set it to FALSE to import it into the primary mailbox.
   • TargetRootFolder: If you want the PST to go into a specific folder (e.g., a folder called “Imported Emails”), specify that here. Leave it blank to import everything to the mailbox’s root folder.
7. Save your changes once you’ve filled out the file.

Note: For point number 3, you encounter issues during the PST mapping file validation. If you do, you can try adjusting the settings. However, it is safe to leave the settings as they are. Nowadays, this error is not commonly seen.

Note: The above table highlights case sensitivity to avoid PST mapping validation errors.

Tip: Double-check the email addresses in the Mailbox column. If even one is incorrect, the import could fail for that mailbox.

6. Upload the PST Import Mapping File

Once your mapping file is ready, it’s time to upload it to Microsoft 365:

1. Return to the PST import job, check both boxes, and click Next.
   • If you are accidently closed this page you have to reopen the page and again need to create one more SAS URL session to view the PST file in Azure blob storage and the section of the check boxes
2. Click on Select mapping file.
3. Browse to the PstImportMappingFile.csv file.
4. Click Validate.
5. If the text appears in green, it means the file is valid. Click Next.
6. Review the PST import job and click Submit.
7. The upload to the cloud has succeeded. Click Done.

Note:
If you accidentally close this page, you will need to reopen it. You must create a new SAS URL session to view the PST file in Azure blob storage. This is also necessary to access the section with the checkboxes.

Once you have finished viewing your file in Storage Explorer, don't forget to detach the session. Leaving it active may cause issues during the PST upload and import process.

Note: I encountered an issue during the PST mapping file validation. This was due to a mistake in the PST file name. The problem was case sensitivity. Please ensure you closely review the "File path & PST name" for accuracy.

Note: We are not done yet; there is one final step: starting the PST import to Microsoft 365.

7. Start the PST Import Process to Microsoft 365

Now that your PST files are uploaded and mapped correctly, you can begin the import:

Before you can begin importing the PST file to Office 365, you must wait for the analysis process to complete. Once finished, it will display the “Import completed” status and be ready for the next steps.

1. Select the checkbox in front of the Import Job.
2. Click on Import to Office 365 button.
3. Select No, I want to import everything. Click Next.
4. Select Yes, I want to filter it before importing. Click Next.
5. Upload to the cloud succeeded. Click Done.

Note: Select Yes, I want to filter it before importing. Click Next. you can filter out the required data to be imported.

Tip: Depending on the size of the PST files and the number of mailboxes, the import may take some time. You can continue working while this process runs in the background.

8. Check the Status of the Import Job

Once the import has started, you can track its progress:

1. To verify the status of the PST import job, click on the Import Job in the list view. Ensure that the PST import job displays a status of “completed.”
2. Look at the status of your import job. It should show progress updates and any potential errors.
3. Successfully imported a PST file to Microsoft 365.

Tip: If you encounter errors, click on the job to view detailed logs. This will help you troubleshoot the issue and try again if necessary.

Conclusion: Wrapping It Up

Importing PST files into Microsoft 365 is a multi-step process. By breaking it down, you can easily manage each part. Make sure to assign the correct roles. Upload the files securely. Map them to the right mailboxes. Monitor the import process. By following this guide, you’ll be able to migrate all your emails with ease and precision.

Note: Reference Microsoft Article
https://learn.microsoft.com/en-us/purview/use-network-upload-to-import-pst-files
https://learn.microsoft.com/en-us/purview/faqimporting-pst-files-to-office-36