Export As MHTML
First launch the A2Z Migrations for OST to PST software. After that you need to go to the Add File option and choose the Outlook OST >> Open.
Now you need to click on Preview button after adding the OST.
Once you click on Preview you will get the all the OST data in front of you with all attachments or folders. After getting the preview click on Export option.
Now an export window will be appear on the screen. Here you will get multiple options like Export All Folders, Selected Folders All Contacts and Calendars. You just need to choose one of them as per your choice. After that, in the Export Option you need to select MHTML >> Browse the destination location where you want to download the exported file >> Export.
Once you click on Export the OST to MHTML conversion process will start.
When the process finished you will get the confirmation message.