How to Backup OST File in Office 365, Exchange, Gmail, G Suite, IMAP?

admin | email backup email converter Office 365 software technology | 5 minutes read | Modified on: 07-11-2019

In the segment, we are going to discuss about how to backup Outlook data file OST in Office 365 environment. Two different methods has been discussed that can help to move OST file to O365 account. If you are looking a way for the same, then you are at the right place. You can perform the process by utilizing two solution one is direct i.e. OST Converter and another one is manual that includes multiple steps.

How to Backup Outlook Data File OST in Office 365?

Any direct manual method is not available. Still, if you want to migrate OST to Office 365 manually, then at first, you need to move OST data to PST and by Drive Shipping/Network Upload method, you can transfer PST file to Exchange Online cloud account. Apart from this, you can download OST to Office 365 Converter that allows to directly upload all its data items to OWA. The application help to backup OST emails, contacts, calendar and other folders of OST to O365 directly.

Here, both methods are discussed for backing up Offline Outlook OST files into Office 365 account. You can check out both the solutions and opt the one that suits you.

Solution 1. OST to PST Conversion + Upload PST to Office 365

It is indirect approach to backup Outlook data file OST in Office 365. First transfer OST data to PST and upload PST files to O365.

Method 1. Backup OST file to PST

  1. Open MS Outlook >> Click File >> Select Import and Export option from the list.
  2. Now, choose Export to a file >> hit Next.
  3. Export to a file window screen will appear >> choose Personal Folder File (.pst) and hit Next.
  4. Select email/folder and click checkbox of Include Subfolders and tap Next.
  5. Click Browse, choose location to save file and select option of Replace duplicate with items imported and hit Next.
  6. Apply password, if required otherwise click OK.

Note: If you are working without the connection of Exchange Server then the mentioned method will not execute. In this case, it is better to opt cost-effective OST to PST Converter tool for direct conversion of OST files to PST.

Method 2. Upload Resultant PST to Office 365

Step 1. Login to Office 365 profile >> Go to Admin Center >> Click Exchange.

Step 2. The window of Exchange Admin Center will display >> Go to Permissions >> double-click on Organization Management >> Dialogue box will appear, click +sign >> Select option of Mailbox Import Export >> Click Add >> hit Ok.

Step 3. Again, select Mailbox Import Export >> click Save.

Step 4. Navigate to Admin Center >> click Setup >> select Data Migration >> tap Upload file.

Step 5. Press New Import Job >> enter job name >> click Next.

Step 6. Click checkbox of Upload your date >> click Next.

Step 7. A window will display, click Show Network Upload SAS URL. Copy and paste URL in Notepad. Now download Azure AzCopy. Hit Run and tool will installed.

Note: When importing PST files to O365, give access to file/folder that you want to import and copy Network Path.

Step 8. Open Microsoft Azure AzCopy tool and type AzCopy.exe/Source:\Network Path or File Location/Dest:”SAS URL”/V: location path where you want to save log file/AzCopy.log/Y

Sample Code:

AzCopy.exe /Source:\DESKTOP-MPKVU38UsersleDesktopImport /Dest:”” /V:c:UsersleDesktopAzCopy.log /Y

Step 9. Hit Enter.

Step 10. Once PST file is uploaded, generate CSV to map resultant PST file into mailbox account.

Step 11. Open window of Import data and select both options and hit Next.

Step 12. Click option of Select Mapping File >> Now upload CSV file >> Click Validate >> Hit Save.

Step 13. PST file is now uploaded successfully to Office 365 account >> Click Close.

Solution 2. OST to Office 365 – Direct Migration Solution

The above-mentioned procedure is complex and will take lot of time. So, if you are unaware of Microsoft Azure Azcopy Tool or Powershell Commands, then it is recommended to go for direct, cost-effective and secure application i.e. OST to Office 365 Converter. The GUI is simple to use and includes easy steps for precise OST file to Office 365 migration with emails, contacts, calendar and other items. Follow the steps and directly backup Outlook data file OST in Office 365 account:

Step 1. Download OST to Office 365 Converter on any Windows OS.

launch ost file converter tool

Step 2. Go to button of Select File/Folder and use Add File, Add Folder, Load Outlook Profile option to load OST files or folder for backup.

add OST file

Step 3. Software load all the data items of OST file with checkboxes on the left software pane. With the help of these checkboxes, you can select the desired mailbox and move to Office 365 account instead of backing up all folders.

select data items of OST

Step 4. Navigate to Saving options and choose Office 365.

choose saving option

Step 5. Enter the login details of the same in which you want to backup OST data. If you have Office 365 Administrator account then select the checkbox of I am Admin. Simultaneously choose sub-options to get desired output. Click Next.

set options

Step 6. If you have chosen I am Admin, then Mailbox Mapping screen will appear showing tabs of OST users, Office 365 users and Select. Click on Select option, multiple account list will appear, choose the desired one in which you want OST data.

set options

Step 7. Finally, click on Convert to start the process. Once done, you will get an alert message on the screen “Conversion Done Successfully”.

process completed



With the help of the steps, one can quickly and effortlessly backup Outlook data file OST to Office 365 account. Download freeware edition of the tool that allows to backup first 25 OST files to Office 365 directly with emails, contacts, calendar and other items. By utilizing the OST Converter FREE DEMO, one can check the software working and features before buying the license key.