I am facing an issue with one of my old Outlook OST files. I recently moved from Outlook to Zimbra, and I need to convert my OST file into TGZ format. I tried searching online, but did not find a reliable manual method. The OST file was created on my previous office laptop, and I no longer have access to the original Exchange account. Can anyone guide me on how to convert an OST file to a TGZ file? Is there any manual method, or do I need to use a third-party tool?