If you want to convert your OST file to PST you need to have some technical expertise to perform this conversion
Converting OST to PST with the Import/Export Feature
• Open Outlook and navigate to the file.
• After choosing the Open & Export area, click the Import & Export feature.
• In this window, select Export to a File; then, select Next.
• After choosing the Outlook data file (.pst), click Next.
• After selecting the folder, you want to export, just click Next.
• Click the Browse option to select the path of the output.pst file.
• After choosing the alternative duplicate management solution, click Finish.
• Click OK to proceed after entering the password to secure the PST file.
However, this method was not recommended by most of the users because of lots of restrictions and limitations with this method such as the process of conversion being time-consuming and complex, the risk of OST file corruption, and also no assurance that all data can be converted or not. So, you can utilize
ToolsBaer for OST to PST Conversion Software with the help of this utility you can convert your bulk OST files to Outlook in PST format with this software. All of your data and attachments can be precisely and effectively exported using this program. All versions of Microsoft Windows are compatible with this program as well. Additionally, a free demo version of the program is available.