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How to Migrate OST File to O365 with The Tool?


Welcome to the MailsSoftware official site. By using this cost-effective solution, users are able to upload Outlook offline OST file information in Office 365 in multiple ways. Follow these steps according to your needs.

Step to Follow:-

Steps:1 Download and install the MailsSoftware OST to Office 365 Migration Tool >> activate the Licensed Version by using the appropriate key.


Steps:2 Click on the "Add File" option to load OST file


Step:3 Select "Add File" or "Search" option to browse OST file >> Click on "Scan" button >> Click on OK.


Step:4 After a complete scan of OST mailbox information The software creates a clear view of OST mailbox , without altering the folder hierarchy in its original form.


Step 1: If you are looking for single OST mailbox to Office 365 uploading, then click on "Export" option.


Step 2: Now you will get "Export" window. From here you can export OST mailbox data in two types -

Export All Folders
Export Selected Folders
  1. Now select Office 365 in Select Export Option Section
  2. You can export OST mailbox data in O365 by choosing one of them option – Export to Primary or In-Place Archive mailbox >> Select any export option >> Apply Date Filter (Optional).
  3. There is one advanced option – Create Log file >> Provide Location to save Log file (Its optional option).
  4. Click on "Next" button to process.

Step 3: Now provide Office 365 Login credentials.


Step 4:After Office365 login, OST to Office 365 migration process will start automatically. Now you are ready to use OST in Office 365.




There is one more advanced option to import multiple OST mailboxes in Office 365. With the use of this latest OST to Office 365 migration tool, you can easily use OST files in O365 in bulk. First of all create CSV file with OST file location, Office365 Email ID and Office ID password. Follow these steps –



Step 1: Click on "Bulk Export" option.


Step 2: After clicking on "Bulk Export", you will get a new window for uploading CSV file –

  1. Click on Browse option
  2. Select OST file to import in O365
  3. Select Mailbox – Primary or Archive mailbox >> Provide Location to save Log file (It's Optional) >> Select Contacts or Calendars to export (It's optional)
  4. Click on "Next" button

Step 3: The software will start automatically OST to Office 365 migration process in bulk –



If you are looking for Impersonate Exporting OST to Office 365, then there is one method for the same. Create CSV file with OST file location and Office 365 Email ID only, there is no need for Password of Office Login ID. Now follow these steps –



Step 1: Click on "Impersonate" option from menu bar –


Step 2: Now check "Impersonation Notification" >> Click on OK


Step 3: Provide correct Login information of admin account or user account (Which has complete access of other account).


Step 4: Browse CSV file of OST information >> Select OST file >> Create New Folder in Primary Mailbox (It's Optional) >> Provide destination path to create Log File (It's Optional) >> Click on "Next" button –


Step 5: Now you will get connecting window –


How to Search Emails in OST file?

If you are looking for particular email from OST file, then follow these steps –

Steps:1 Click on "Add file" option and browse OST file from local folder of your machine.



Steps:2 After successfully uploading OST file in this OST to Office 365 Migration tool, it will generate the complete file preview of OST mailbox >> Click on "Search Mail (s)" option.


Steps:3 The software provides multiple filters to find the emails from OST mailbox. You can apply any filter to search email. Follow these steps –

  1. Select mailbox folder from left panel
  2. Provide any filter – To, From, Subject, Received After, Received Before, and Received on
  3. Click on "Search"
  4. Select emails
  5. Click on "Export"

Steps:4 Provide Office 365 Login Information.


Steps:5 Now you will get confirmation-message.