OST file in Outlook Windows
OST is a format that is similar to PST, the native file format used by Outlook. Where PST stands for Personal storage table and is a personal data file that can be used manually for data import/export, backup, and all sorts of purposes, OST is mainly for offline use. When you add a general IMAP account to Outlook that syncs with the servers, Outlook downloads the data to local OST files that are stored in the database folder in your computer. This file is in sync with the servers constantly but also lets you work even in an offline mode.
But there are instances where you might be left with isolated OST files, and unlike PST, you cannot directly use them with Outlook manually. You cannot double-click on an OST file and open it with Outlook, or use the File à Import feature of Outlook to import them. They are also not compatible with any other client. So, that brings us to our question, how can you open OST file in Outlook Windows. The simple answer is that you cannot, at least, not directly.
This file isolation, which means that OST file is isolated from the main account with which it was associated with, can happen due to many reasons. Such as virus attacks, accidentally deleting account before the data was synced, network failures, data corruption, and much more. But let’s not focus on why it happens, but instead move on to the solution.
Cannot open OST file in Outlook? Here’s what to do:
You can easily get the data in OST files back to Outlook by converting OST to PST. As said above, PST is the native Outlook data file in Windows, and it also works with the Mac Outlook for importing data. You can manually open PST file by double-clicking on it or even by importing the file to Outlook. PST is an open proprietary file format by Microsoft that has a large capacity for storing a lot of data. It can also be used as a backup file to be used later in the future when you want to restore it.
But OST to PST isn’t as straightforward as it sounds. Even though OST and PST are the variant of same format, there are also some differences internally in their structure and the way information is parsed, converting them can become a nuisance and time consuming. But we have a perfect solution for this.
The tool that you need…
USL Software’s tool called “OST Extractor Pro” works brilliantly for this. It is available to be used in both Mac OS and Windows platform and has special algorithms to convert all kinds of data and elements from OST to PST without loss or modification. It also features many options that were previously missing from the ordinary converters, such as manually removing folders you do not want to convert, ignoring empty folders, splitting large PST files, and much more. In fact, OST Extractor Pro brings one other excellent feature and that is allowing you to convert OST to many other formats, not just PST. You can choose to convert OST to MBOX, EML or directly to Apple Mail, Thunderbird, or Postbox format.

If you want to move data quickly and safely in OST to Outlook, but found out that you cannot directly open OST in Outlook, “OST Extractor Pro” is the way to go. It works with fast speed and has a simple interface that requires no technical expertise. Get to the official download page from the link below and you can get started with a free trial version if you wish to see it in action.