Badly damaged OST file

An OST file (.ost) is an offline folder file in Microsoft Outlook. Offline folders make it possible for the user to work offline and then to synchronize changes with the Exchange server the next time they connect. The ability to work offline is useful in environments with limited or unreliable connectivity

We have received a very badly damaged OST file.  Moreover, it was 6GB in size and recovering it and converting it was a lot of work!  Outlook provides a way of repairing the content of these files, but the user had already tried this to no avail!  Our engineers used proprietary software to recover the lost mailboxes, and individuals emails. Following a full scan the damage was repaired and when we checked the subsequent OST file, we had overcome all the errors. The OST was converted to PST and checked 100% error free using Outlook 2010. No major corruption apparent anywhere.  It's was copied to a DVD and dispatched to a very happy client.