I have several orphaned offline folder (.ost) files, and I want to extract whatever data I can from them. Which recovery tools work on .ost files?

When a user deletes the Messaging API (MAPI) profile associated with an .ost file, the .ost file is usually rendered useless because there's an encrypted token whose value derives from the profile stored in the file. Thanks to Exchange Most Valuable Professional (MVP) Andrew Sword for pointing out the ExchangeRecovery tool (http://www.officerecovery.com/exchange). Although I haven't tested the tool, its developer claims that it can recover at least some of the data from an orphaned .ost file. Download the trial version to test on your files, then order the full version of the ExchangeRecovery tool if it seems useful.