OST files are the files that are used when the server collaborated environment is established. The OST files are carriers of unsaved data that are altered while working offline also, i.e. the OST files allow the working with the files even when the server is in off mode. The normal scenario is that the changes made with the offline files will get synchronized with the server mailbox, once the connection with the server is reestablished. But the condition become problematic when the normal synchronization is blocked with the situations like OST Corruption, server crash etc leading to the inaccessibility of data that are within the OST files only.
Being Offline also user can send and receive emails, as actually the emails are stored in the outbox folder.Since drafts and received items can be made and check respectively in the offline mode, OST files need to be saved from data corruption.The best way to save them before they get damaged is to convert OST file data to PST file format. For viewing OST Emails in PST the best available option is to Convert OST data to PST with the OST2PST Software.