OST is a file used by Windows Outlook, but it is not PST. The difference is that PST can be used by users to import, export, backup, archive, etc. any way they way. OST on the other hand is not suitable for that. But if they are looking for a tool for opening OST fie in Office 365 Outlook client, there is an easy and efficient one from USL Software.
Office 365 is a set of software within a subscription model that includes Word, Outlook, Excel, and more. For this article, Office 365 means Outlook client only.
How to Open OST file in Office 365
First, it is crucial to keep things simple and that means clarifying the nature of OST file. OST stands for ‘Offline Storage Table,’ which is a variant of PST file, which stands for ‘Personal Storage Table.’ And this means that there is no way to directly open OST file in Office 365 Outlook client.
You can check this. Start Outlook in Windows, click ‘File’ à ‘Export/Export’ à Import from another program or file. Here you can see the list of available formats you can use to import data. Most of the files except PST are for contacts or other lists items, not for mails. To import email messages, only PST is the available format used in Windows Outlook; it is also used in Mac version of Outlook for importing.
Therefore, when we will talk below about the software of USL Software, it should be noted that it only helps in converting OST to PST, not for opening OST file in Office 365. But importing PST serves the same purpose.
“OST Extractor Pro” – Reliable OST Conversion App (Cross-platform)!
The tool from USL Software is called ‘OST Extractor Pro.’ It can convert OST files to other formats which includes Apple Mail, Thunderbird, Postbox, MBOX, EML, and PST (which is the only format we are concerned with in this article).
Here is a brief guide on how to use the tool:
- Once installed and launched, click on ‘Add OST’
- Browse to the location of OST files and select them.
- You can uncheck any folder to exclude them from conversion.
- Click ‘Start’ and choose a location for the tool to save the converted PST files
- Once finished, launch Office 365 Outlook
- Go to ‘File’ -> Import/Export -> Import from another program or file
- Browse to the location of converted PST file and select it
- Now you can see all the data from the converted PST file inside Outlook
The output PST file can be used with all previous Outlook versions, not just in Office 365. Also, the OST files from legacy versions of Outlook can be used for conversion.
OST Extractor Pro is backwards compatible. It is also cross-platform, available for Mac OS X and Windows. If you are using it in Mac OS and Outlook is in Windows, the only extra step is that you need to move the converted PST files to Windows computer and vice-versa if you are using the app in Windows PC but Outlook in Mac.
Download the setup file below for free. Double-click on it and install. It will take only two minutes to set it up and start running. No configuration required to set it up for the first-time use. It can convert OST to PST without Outlook installed on your system.
Simply launch and follow the steps outlined above. Pre-activation (trial) works on ten emails from each folder but there are no restrictions on the number of folders or in the functionality. So, you can test all its features in full detail exactly as they work in full version.