If you wish to export encrypted OST file to PST file, then you would have to use OST to PST Converter software.  To use this software, you would have to download, register, and then launch the software on your Windows system. To run the software, you would have to execute the following steps:

Step 1: Double-click on the icon of Stellar Converter for OST software. When you do so, the home screen of the software that provides two options to select encrypted OST file comes up.  

Step 2: To select Outlook Mailbox (OST), click on the 'Browse' or 'Find' button. Choose the former if you are sure about the location of encrypted OST file else choose the latter.

Step 3: If you choose 'Browse' option to select Outlook OST file click on 'Convert' button on the same screen for the software to start the conversion process. This process of conversion can take several seconds to few hours. The time taken for conversion depends on the size of the encrypted OST file.    

Step 4: If you choose 'Find'  button, then Find Mailbox screen comes up. 

  1. In it, click on the Look in the dropdown menu to select the drive in which you think the OST file is present. You can also click on the Look in and then Start tab so that the software starts searching the OST file.   
  2. After some time, the software showcases all the OST files in the Find Results section. Choose the encrypted OST file you wish to convert and click on the 'Convert' button. 
  3. Click on the Scan Now button for the software to start the conversion process.

Step 5: The conversion process completes in some time depending on the OST file size. Then, all the objects of the OST file shows up in the left pane of the preview window in a tree-view format. The data of a particular folder is shown in the middle pane whereas the details are shown in the right pane.  

Step 6: Choose all or particular data items which you wish to save in PST file format and click on the 'Save Converted File' button present in the File menu. This gives multiple saving options out of which one is PST file format. 

In this way, by following all the steps that have been stated above you can easily export encrypted OST file to Outlook PST file format. Thus, use Stellar Converter for OST and achieve your target!