I recently deleted a whole bunch of log files from Exchange, which, of course, screwed me up. I've since gone through and fixed everything and merged live emails with ost files (from cache mode) and have everybody's email up to snuff here in the office.
The process was: export ost file as pst file in offline mode, go back into connected mode and import the pst file, disable cache mode, disable offline, exit outlook, go back in and reenable cache mode and rename ost file.
This put us back where everything was cool
My only problem now is users on the outside that connect via OWA...how do I get their old emails back?