After PST, the most widely used file format of MS Outlook is OST. It is created when your Outlook profile is configured with MS Exchange Server when Cached mode is enabled.
OST stands for Offline Storage Table which is a local copy of the mailbox folders but it is created on Server. Even the server is down, users can work on OST. Any changes made in the folder at client or server are updated. The process is known as synchronization. Like PST, OST allows users to save data in an organized manner. It saves Outlook databases in several folders by creating categories like Inbox, Outbox, Drafts, Sent Items, Calendars, Notes and Tasks.
Technical Key Features of OST
MAPI clients can access the items of OST without establishing a connection with the server. The Folders saved in OST is the copy of the mailbox folders saved on the Server. It requires users to authenticate to access the data because it automatically encrypts content.
While integrating the MS Outlook with Exchange Server, an encryption key is generated which is saved in the mailbox on Server and in the MAPI profile.
During access of an OST file, the key of the mailbox and the MAPI is matched. The OST file is not opened until the key is matched. If the key is not matched due to any reason, access to the particular OST file is not possible.
Exchange Server helps an organization to secure their data and allows private messaging. The encryption of OST is valuable for the organization. When users try to access OST in a different profile, it becomes inaccessible.
Points to Notice
- An OST file cannot be opened in the different MAPI profile.
- Synchronization process takes place automatically. However, a special synchronization process for the public folder replicas is generated by the user.
- The encryption process takes place by default. Therefore, no password protection is required.
- Users cannot access more than one OST file at a time.
Outlook 2013 Update for OST
With the launch of Outlook 2013, Microsoft had changed the handling process of IMAP. With access to an IMAP mail account, an OST file is created. The OST file of IMAP has the same feature as the OST file with Exchange Server.
Problems with OST Files
Exchange Server Mailbox and OST file are related to each other. It is protected with the MAPI encryption key. When the mailbox disconnects with the OST file, it becomes orphan and inaccessible. When the mailbox is deleted due to any reason, OST files get orphaned.
Corrupted OST Files
An OST file can corrupt because of varied issues. Hardware and software related issues when arise it may corrupt the OST file.
Uninterrupted functioning of OST files can be achieved only when it is properly configured with Exchange Server. In the absence of configuration, errors can occur which can influence the normal functioning of OST files. It can cause file corruption.
Troubleshooting OST Files
OST Integrity Checker
OST Integrity Checker is a free tool which is offered by Microsoft to know the synchronization issues between Exchange Server and OST. It evaluates and repairs the issue like Scaost.exe.
Transfer OST to PST
If facing the file size issues, all you need to export OST to PST. In this condition, you may take help of a reliable software like Softaken OST to PST.