If you have an OST (Offline Storage Table) file and want to access its contents in Microsoft Outlook, it’s important to understand how OST files work and how to properly open them. OST files are typically linked to an Outlook account (such as Exchange, Office 365, or IMAP) and cannot be opened directly in another Outlook profile without conversion. Here’s a simple guide to help you Open OST file in Outlook.

What Is an OST File?
An OST file stores a synchronized copy of mailbox data from the server, allowing offline access to emails, calendars, and other items. It is automatically created when you set up an Outlook account using Exchange Server or Office 365.

Can You Open OST Files Directly in Outlook?
No, you cannot open an orphaned OST file directly in Outlook. If the original Outlook profile or account no longer exists, the OST file becomes inaccessible through Outlook.

Methods to Open OST File in Outlook
Method 1: Reconnect the Original Outlook Profile
If the original account is still active:

• Open Outlook.
• Go to File > Account Settings > Account Settings.
• Reconnect the account using the same login details.
• Outlook will automatically recognize and load the OST file.

Method 2: Convert OST to PST File
To open an orphaned or inaccessible OST file, convert it to a PST format first using a reliable OST to PST Converter tool:

• Download and install an OST to PST converter.
• Add the OST file to the software.
• Convert and export it as a PST file.
• Open Outlook and go to File > Open & Export > Open Outlook Data File.
• Select the converted PST file to access your emails.

Recommended Tool
Use Advik OST to PST Converter – a secure and efficient solution to extract data from OST files without Outlook. It preserves folder structure and ensures no data loss during conversion.

Final Thoughts
You cannot directly open an OST file in Outlook unless it's linked to its original profile. For all other cases, converting OST to PST is the most effective method. Using a dedicated OST converter tool is safe, easy, and ideal for restoring access to your important emails.