CopyPST is a program which repairs Outlook data files by exporting it to a new file, ignoring any error. It requires that the data file can still be opened in Outlook. Exporting a file also makes it much faster however you need to repair links, afterwards using OLfix.
You will use first SCANPST to repair a damaged file, if this does not help, you can use the export function in Outlook. However MS products like to abort any copy operation after the first error. CopyPST ignores all errors and therefore is able to copy the whole file.