Free Methods to Import OST Emails Microsoft 365

Microsoft 365 has become the top-most cloud service coming from Microsoft. It has hundreds of millions of users worldwide and earns the maximum benefit for Microsoft. Although, Exchange Server is the primary email server that the businesses employ, Exchange Online present in the Microsoft 365 Enterprise and Business gives more flexibility to access the emails universally.

The security levels of the mailboxes remains the same like on-premises Exchange Server, but are accessible at any device or location. When the users want to migrate from on-premises Exchange to Microsoft 365, then they need to migrate both OST and PST files. The Offline Data File (OST) is the replica of the Exchange mailbox data while the online data file (PST) contains the important emails, contacts, notes, sent items, attachments, calendar details, etc. Whenever the connection between Outlook and Exchange Server is down, then the Outlook account remains active due to the OST file. Later, the data is calibrated with Exchange Server when the connection is active again. A user tends to move OST data to Microsoft 365 due to many reasons like advanced benefits of Cloud, prevention of Exchange downtime, need of secure environment, organization shift or migration, etc.

In the present article, we will discuss the manual methodologies to import OST files emails to Office 365. There is no direct method to place your OST files directly to your Microsoft 365 accounts. The user has to create some workaround strategies to convert and import/export the data.

Method 1. Convert OST to PST and Import PST to Microsoft 365

The first manual method is an indirect method where you can convert the OST files data to PST and then import the PST file to Microsoft 365 because Security & Compliance of Microsoft 365 supports the import job of PST files.

Here are the steps to create the PST files;

  1. Start Outlook and click File option.
  2. Go to Open & Export and click Import/Export wizard.
  3. After opening the Import/Export wizard, choose the option ‘Export to a file.’
  4. Select the second option ‘Outlook Data File (.pst)’ and click Next.
  5. The wizard will present you all the folders of the Outlook OST mailbox account. Check the option Include Subfolders and click Next.
  6. Click the Browse button to mention the location of the PST file. Also, choose among the options that you handle the duplicate items. Then click Finish.
  7. A new PST file has been created including all the data of your OST mailbox account.
  8. Note: One cannot migrate OST file data like message rules, folder properties custom views, meeting schedules, etc. using the above method.

The second process requires you to import the PST files at the Microsoft 365 using either the Network Upload or Drive Shipping methods.

Note: It is crucial to assign the Mailbox Import Export role to the Microsoft 365 mailboxes before starting the process. For that, logon to the Exchange Admin Center of the account, go to Permissions and open Organization Management by double-clicking the mouse. Click on Add option and then add the Mailbox import-export role and click on Save finally to save it.

Network Upload Method

The Network Upload method helps you to migrating multiple PST files at the same time. We are providing you the steps of the method in a precise manner;

Download the AzCopy tool and get the SAS URL of your organization

The AzCopy tool is required to run the network upload method and the SAS URL is a collective URL of the network URL of Azure Storage location and Shared Access Signature Key.

  1. Login to or your organization with the help of Administrator credentials.
  2. At the Security & Compliance Center, choose the option to Import PST files and click New Import Job.
  3. Choose the first option to Upload your data.
  4. The next page will ask you to Copy the SAS URL for network upload and use the AzCopy tool to upload the PST files.
Use AzCopy tool to upload PST files to Microsoft 365

The AzCopy tool uploads the PST files directly to the Azure Storage location of your organization.

  1. Open the command prompt as the Administrator.
  2. Go to the folder location where you have installed the AzCopy Tool and run the command –
    AzCopy.exe /Source:UNC-Path-of-PST-File /Dest: /V: /Y
  3. Note: Enter the PST file (to be uploaded) path and the SAS URL copied earlier in the previous section.

Create Import Mapping File

After you have saved the PST files at the Azure Storage Location, you need to create a comma-separated-value (CSV) file that will have the name and details of the Microsoft 365 mailboxes that will have to save the PST files. You can create the CSV file by mentioning various properties like workload, FilePath, Name, Mailbox, TargetRootFolder, ContentCodePage, etc.

Create a new Import job for PST files

You again need to go to the Security & Compliance center at Microsoft 365 Admin Center and choose the option New Import Job.

  1. Choose the option ‘Upload your data.’
  2. Click the checkbox the two options – I’m done uploading my files and I have access to a mapping file.
  3. Click the Select Mapping File button and upload the earlier created CSV file.
  4. Click the Validate button to verify the content of CSV files.
  5. Click Save to submit a job.
Start the PST Import Job and filter the data

The new Import Job will check for the selected data and allow you to filter the data from the PST file. After making all the changes, start the migration.

Drive Shipping method

Drive Shipping method saves you from the long and tiresome procedure of the network upload method. If you choose the Drive shipping method, you only need to create the PST files copy these files to Drive and contact Microsoft. A Microsoft Official will collect the PST file from you or you can ship the drive to Microsoft Office from your end and upload it to the Microsoft 365 mailbox. But this process is also not suggested mostly as it would take about 10 days to ship the PST file from PST to Office 365 via Microsoft official.

Method 2. Use a Professional software

Professional software is your option to conduct any migration towards Microsoft 365. It does not require any lengthy procedure or prerequisites but only the data from the PST files and the credentials of your Microsoft 365 account only. You can purchase any suitable software that has all the advantages of the migration.

Our recommendation is the most efficient OST to Office 365 migration tool to migrate OST or PST files to Cloud platform directly and securely. Visit the tool website to get completion details about its features. Get started for the exclusive migration!