An OST (Offline Storage Table) file is an Outlook data file used by Microsoft Outlook to store a local copy of mailbox data when connected to an Exchange Server. The primary purpose of an OST file is to allow users to access their mailbox data even when they are offline or not connected to the server.

There could be several reasons why you might be unable to open, view, or read an OST file:

1. Incompatibility: OST files are specifically designed to be used with Microsoft Outlook and are not intended to be opened directly or viewed outside of Outlook. If you are trying to open an OST file using a different program or software that doesn't support OST files, you may encounter issues.

2. Corruption: OST files can become corrupted due to various reasons such as abrupt shutdowns, hardware failures, software conflicts, or synchronization issues. When an OST file is corrupted, it may prevent you from accessing its contents. In such cases, you may need to repair or recover the OST file using specialized tools or techniques.

3. Synchronization Errors: OST files rely on synchronization with the Exchange Server to update and store the latest mailbox data. If there are synchronization errors or issues with the Exchange Server, it may cause problems with the OST file. This can result in an inability to open or view the contents of the OST file.

To remove the above hurdle we need to use the Data Recovery Freeware OST Viewer Freeware. This OST Viewer Freeware helps to open, view and read OST file with attachments such as contacts, calendars, email messages, tasks, journals, etc. However, this tool helps to save the OST file into TXT and HTML file formats. It gives you best easy to use GUI/UI that makes this tool easy for everyone. OST Viewer Tool compatible with all the versions of MS Outlook. To explore the other features of this tool you can try the demo version of this tool.