What data file types does Outlook support? While working with Outlook, you will encounter two data file types: OST and PST. OST (Offline Storage Table) file types allow you to work offline.

Your Outlook Data File is composed of a file header, located at the beginning of the document, and the actual data that makes up your personal folders. Contained in the header is information about ...

A File Cannot Be Opened in Microsoft Office Outlook. If you cannot open Microsoft Outlook for some reason, it can make communicating with employees, clients or suppliers rather difficult in some ...

One prevents the body of an email from being displayed In Outlook Express & the other apparently prevents an MHT file form opening locally. I have reversed the change & now the files open normally ...