Differences between Outlook PST and Outlook OST Files 

The MS Outlook is one of the most popular platforms in the world due to its robust functions. Many people use the MS Outlook data files such as PST and OST files frequently, but not all of them are aware of their differences. 

You should know the differences between the PST and OST data files so that you can implement proper strategies to prevent them from crashing from repair them from corruption. In this article, we will discuss some great differences between Outlook PST and Outlook OST files. 

What are MS Outlook PST Files?

The PST files are one type of MS Outlook data file. The file contains local copies of your mailbox items such as messages, calendar events, contacts, task data, notes, and more. The structure of the PST files is designed in such a way that it would help you import and export your messages, calendar events, contacts, tasks, and notes to any device you want. 

POP accounts save all the essential data in the PST file format. However, remember that the POP protocol is a traditional email protocol where the emails can be downloaded in your system locally and can be removed from the server you’re using. This helped users in the past as most of them didn’t have multiple devices to access emails. The primary objective of the POP accounts was to store the contents of emails in your local drive and provide you with an option to delete the emails from the server. However, this feature does not apply to modern users as they can have multiple devices to access emails. 

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If your email client is dependent on POP, the changes that you make to the emails that are stored on the device won’t affect the copies that are stored on the server. Here are some features of the Outlook PST files:

  • They cannot be synced with the email server. 
  • You will be able to access mailbox items without the internet. 
  • They can be password protected. 
  • They can be converted into other file formats. 

What are the MS Outlook OST Files?

Just like the PST file formats that are used in the POP Accounts, the OST files are implemented in IMAP accounts. Just as the POP, the IMAP is also another effective email protocol that is attached to different Outlook accounts such as MS 365 Accounts and MS Exchange Accounts. 

The OST files that are used by the IMAP accounts store the synced copies of your mailbox items in the device. However, unlike POP, the actions you perform on the IMAP will also affect the copies that are present on the server. This means that if you use the IMAP email client, deleting the email items locally will also remove them from the server. But the actions will take place as long as you have a stable internet connection. 

Therefore, the IMAP protocol is most effective for every day. Unlike the PST files, the OST files can be synced with the server. You can also access your files with/without an internet connection. 

Outlook PST Files vs. Outlook OST Files 

The PST and OST are both file formats of MS Outlook. They can be used to store essential mailbox items. The older version such as 2002 and older MS Outlook versions used to come with bot PST and OST files. Earlier, the size of the file formats was 2GB, and oversizing the file formats would lead to corruption or crash. However, after the introduction of Outlook 2003, the PST and OST files became Unicode variants. The newer version of the MS Outlook comes with a 50GB size limitation. 

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However, even though they are effective, both the PST and OST file formats have become extremely prone to corruption, which can lead to significant data loss. 

Remember that OST files can be synched individually using the server whereas, the PST files can be transferred to the local computer. If you’re planning to use other email services, you will be able to upload PST files as they are compatible. However, you need to convert the OST files so that you can move them into other services. Last but not least, the PST files are safer than the OST files in terms of virus attacks. As per Live Science, antivirus programs will help you prevent virus and malware attacks.

Outlook PST and OST Repair Tool

As we said, the Outlook OST and PST files are vulnerable to corruption. Even if the PST files of your MS Outlook Profile have been corrupted, you don’t need to worry as you can fix pst easily with our PST repair tool. 

However, you need to be patient while using the PST repair tool. Even though our tool will undoubtedly help you fix the corrupted PST files and help you recover the essential data, the speed of the scanning and repairing process is dependent on your system as well as hardware configuration. 


These are the differences between Outlook PST and OST files. If you have any other questions, make sure you let us know. 

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