Microsoft provides an Integrity check tool, aka scanost.exe, to handle corrupt OST files. It is a built-in utility which is available in MS Outlook 2002, 2003 and 2007. The offline storage table, which is commonly known as OST file, is prone to corruption. Corruption may lead to inaccessibility of mailbox data which include email messages, calendars, contacts, tasks, notes, journals, etc. It is quite obvious that corruption in computer files occur due to various unforeseen reasons. But the main reason behind OST file corruption is the interruption which takes place during the synchronization process with Exchange Server.
Whenever you face errors or any symptom of corruption in your offline Outlook data file, you must try the scanost.exe, the Integrity check tool provided by Microsoft itself. Many computer professionals and experts strongly suggest to make the use of this built-in utility to scan corrupt OST files. It is very simple to use scanost.exe to repair OST file, just follow the steps given below:
Your OST file is repaired now. You can try to open it.
Unluckily, the scanost.exe tool is not available in MS Outlook or any later version. Also, Microsoft does not guarantee the 100% result or repairing OST files. In case of severe corruption, the Integrity check tool may fail to repair OST files. In such situation, you can try a third-party OST Recovery tool that can repair OST file and recover your mailbox data from it.
Read: How to use the Inbox Repair tool to recover email messages in Outlook?