How to Import OST File into Office 365

import OST file into Office 365

Ashish Ratan Singh | Modified: August 8, 2017 | Migration, Office 365 | 4 Minutes Reading

An OST file can’t be directly accessed from anywhere. The OST file should be converted into format to be able to access its data on Outlook or Office 365. Now, we have a scenario in which a user wants to migrate to Office 365 or needs to import OST to Exchange Online account. There isn’t any direct manual method which helps to import OST File into Office 365 account.
We have to use 2 methods to do the same i.e first is to convert OST to and then upload file to Exchange Online mailbox. In the following section, we will explore various ways to successfully perform this transfer.

OST to Office 365

Ways to Import OST File into Office 365 Mailbox

In order to move OST file to Exchange Online, we need to follow 2 step procedure as mentioned above. So, first let’s see how to convert OST file to Outlook .

Step: 1 Convert OST file to

There are following few manual solutions to change Outlook data file from OST to :

Solution 1: Export Feature of Microsoft Outlook.

Follow the steps to export files from Exchange OST to Outlook .

  • Start Microsoft Outlook.
  • Click on File → Export to a file → Next.
  • Select Personal File Folder (.) → Next.
  • Select a folder you want to export and check Include subfolders.
  • Now, choose the location to store the exported file and Click on Finish button.

Note: For the above free conversion solution, you must be connected to the Microsoft Exchange Server.

Solution 2: Archive Feature of Microsoft Outlook.

It helps to transfer data to mailbox items to Outlook Data File (.). Try the following steps for this conversion:

  • Start MS Outlook.
  • Go to File → Archive.
  • Select the file or folder for archiving on the new open window.
  • Select the destination for the archived file.
  • Archiving process will start when you click on OK button.

Note: This solution allows you to move entire OST file data except Outlook Contacts.

Solution 3: Export Outlook items to new

This method migrates mailbox items of Exchange Offline OST file into new .

  • Open Microsoft Outlook.
  • Make a new Outlook Data File (.) in MS Outlook Profile.
  • Select the mailbox folders that you want to export in Outlook file.

Note: This method doesn’t allows to drag Inbox, Sent Items, Calendars, Contacts, etc. default folder into a file. So, just copy the folder from Offline OST file to .

Step: 2 Upload File to Exchange Online

After the OST file to conversion, the next step is to move/ save the resultant file into Office 365.

There are three procedures to transfer into Microsoft’s cloud-based collaboration suite. The methods are as follows:

  1. Drive Shipping
  2. Network Upload
  3. Using a third-party utility

Let’s discuss these methods in detail.

1. Drive Shipping

It is a way to move data to OneDrive for Business. First, copy the files to a hard drive (the hard drive should be BitLocker-encrypted) and then physically ship the drive to the Microsoft data center.

2. Network Upload

In this method, just transfer/ copy Personal Storage Table into Exchange Online by consuming less time.

Follow the given steps for this solution:

  1. Copy the SAS URL and install Azure AzCopy
  2. Migrate file into Exchange Online mailbox
  3. View a list of the files uploaded/ saved to O365 (Optional)
  4. Generate the . import mapping file
  5. Create a Personal Storage Table import job in Exchange Online.

Note: Step 1 should be performed only once to be able to transfer PST to Exchange Online mailboxes. Then follow Step 2 through Step 5 every time you wish to transfer bulk/ batch of Outlook Data files.

There are some disadvantages of the manual procedures also. They are as follows:

  • The manual approach is time consuming.
  • The uploading will consume lot of time and labor while migrate large-sized bulk . files.
  • A user must have complete technical knowledge in order to save/ upload Personal Storage Table files to Exchange Online manually.
  • If any of the steps is missed then data deletion/ corruption might occur.

3. Third-party approach to Move OST to Office 365

You can also use a third-party approach to save/ copy OST to Exchange Online. You can convert OST to via a manual method or by using an OST to converter tool.

Also to move to Office 365 mailbox, you can follow the above-mentioned procedures or you can go for a third party tool which can efficiently upload file to Office 365.


After going through the above all solutions, it can be concluded that there is no doubt that the manual methods are free to use but, they are not easy to use as one must have proper technical knowledge while going through the steps to import OST file into Office 365 manually. There is one drawback of manual solutions is that they are they are very time-consuming and can’t be done in a faster way.