Steps to Convert OST to PST Manually
Method 1. Import/Export Wizard
Microsoft Outlook and go to the “File menu” in the upper left corner of Outlook.
Choose “Open and Export” and click on the “Import and Export” option.
A new popup window will open “Choose an action to perform“.
Select “Export File” and then click “Next” to continue.
After that, select “Outlook Data File (. pst)” and click “Next” to continue.
Select the folder you want to export and click “Next“.
To save the PST file browse the location and select the option about duplicate items.
Method 2. Archiving Files for the conversion
Open the configured Outlook application and go to the “File menu” and click “Options“.
Navigate to “Advanced” and click the “Auto Archive Settings” button.
Select the number of days for which you want to auto archive.
Select the location you want, also provide an archiving option and click OK at the end.
I hope this is helpful!
Lewis Bert