I am trying to convert my old email backup from MBOX to PST format so I can open it in Microsoft Outlook. I am using a third-party MBOX to PST converter, but every time the process reaches around 70–80%, the conversion suddenly fails or stops without any clear error message. The MBOX file is quite large and contains multiple folders and attachments. I have already checked that Outlook is properly installed on my system and that I have enough free disk space. Still, the converted PST file is either incomplete or does not open at all. Can anyone explain the common reasons why an MBOX to PST conversion fails in the middle of the process? Also, what practical steps can I follow to fix this issue and complete the conversion without losing any emails?