Sometimes after recovering a PST file it can no longer be opened by Outlook, or, Outlook will report an error with it.

Try this:
If the PST file was fragmented or overwritten, then it may be corrupt.

You can try to repair the file: Get the free Scan PST utility from Microsoft: //support.microsoft.com/?kbid=197315

Once you’ve done that, you’ll be able to open the file from within your email client.