Repairing corrupt Mail
 

I am using Sandbox and OS 10.4.8. There is a problem with Mail- messages disappear from the mailboxes- which appears to be quite common when I search the Apple Forums. The fixes involve deleting several files and rebuilding the mailboxes. But when I look at my original hard disk and the Sandbox, the Mail files are duplicated but the contents appear different. So which files do I delete and where?

A Sandbox shares your user files, including mail, so the files wouldn't be at all different...