# How to Differentiate in Outlook’s PST/OST Files **URL:** https://www.compsmag.com/blogs/how-to-differentiate-in-outlooks-pst-ost-files/ **Author:** Ayushi Chauhan **Published:** 2022-02-14 **Updated:** 2022-02-14 **Categories:** Blogs **Tags:** Blogs Daily, Computer Guides, guiderobert, Guides and Tutorials, guiding12, How To Guide, How To Guides, internet tips and tutorials, office tips and tutorials, Software tips and tutorials, Tips, Tricks **Reading Time:** 7 min --- This tip is about the how to Differentiate in Outlook’s PST/OST Files. So read this free guide, How to Differentiate in Outlook’s PST/OST Files step by step. If you have query related to same article you may contact us. ## How to Differentiate in Outlook’s PST/OST Files - Guide The basic difference between OST and PST is that OST files are used to store data for offline use and stored on MS Exchange Server. While PST files are personal folder data and stored on the client's hard drive. Microsoft is a reputable company that has a pocket full of apps and utilities. And one of the most famous applications is MS Office Suite. MS Office package consists of a huge number of useful applications like PowerPoint, MS Word, Excel, Access which are used by almost all users. One of the most popular applications in the MS Office suite is MS Outlook. It is a personal information manager designed for MS Windows and MAC. Firstly, it was developed as an email client, but due to its richness of features like creating tasks, calendars, journals, notes and even web browsing, it can also be used with Microsoft Exchange Server and even SharePoint Server or even to share multiple files or documents among multiple users in an organization. As an email client, MS Outlook stores all kinds of data like emails, attachments, calendars, journals, tasks and so on. And OST and PST are the file formats used by Microsoft Outlook to store all your above data. ## What are Outlook PST Files Outlook PST file is an Outlook data file. PST file stores local copies of your calendar events, messages, task data, contacts, etc. any device. POP accounts store data in PST format. The POP protocol is an older email protocol (POP3 is the newer version of the same protocol). When this protocol is used, all your emails are downloaded locally to your computer and can be deleted from the server. This made sense in the old days when users only had one device to access email. A system where the email servers put the emails on your local device and made it optional to delete those emails from the server was the case until now. However, these days, that wouldn't make much sense as the average email user accesses their email from multiple devices. If your email client (i.e. the application/software used to access your email from the server) uses POP, any changes made to your email (in the email client) on your device will not affect the server. Vice versa - unless you perform the same action on the server. ### Features of Outlook PST files PST files are not synced with your email server You can access your emails, calendar events without Wi-Fi/data as long as they have been downloaded PST files allow the use of password protection over their content PST is supported by client applications such as Windows Messaging, Microsoft Exchange Client and Microsoft Outlook PST files can be converted to other formats and sent to other email providers like Gmail Outlook PST files can be converted to OST format ## What are Outlook OST files PST file format is used for POP accounts while OST file format is used for IMAP accounts. Like POP, IMAP (Internet Message Access Protocol) is another popular email protocol used by your email providers – which is often the case for Outlook accounts, Exchange accounts, Microsoft 365 accounts, and so on. Your OST file, used by IMAP accounts, stores synchronized copies of your mailbox information on your device. Unlike POP, any action performed via IMAP affects the copying of your files on the server. By default, if your email client uses POP, deleting an email locally does not affect the copy stored on the server. However, if the client uses IMAP, then locally deleted email will also be removed from the server as long as you have an active internet connection. This is the basic idea of ​​“synchronization”. The IMAP protocol is therefore better suited for everyday email traffic, after all, you don't want to delete an email from your computer and view it again on your phone, you? However, POP (or POP3) still has some advantages – depending on the user. If you have an IMAP account, Outlook stores your email in a format that syncs with the server, i.e. in the OST file - as long as you use Microsoft Outlook 2013. In the previous version of Outlook, PST files were used for IMAP and POP protocols. Currently, only POP accounts store emails offline in the Personal Storage Table (PST format) in a form that is not synced with the email server. ### Features of Outlook OST files OST files are synced to your email server Taking an action on your emails also affects the copy stored on the server You can still access your files (previously downloaded) without Wi-Fi/Internet data You can create “send” emails without an internet connection pending when there is a connection OST files are not conventional files that can be password protected OST files cannot be directly imported into other services such as Gmail unless they are converted to PST format first. ## Outlook PST VS Outlook OST PST and OST formats are Outlook data formats. They are used to store your Outlook items (messages, calendar events, contacts, etc.). Earlier versions of Outlook (Outlook 2002 and below) used an extended ASCII with a code page to encode PST and OST files. This initial format could not exceed the maximum size of 2 GB when saving files: Attempting to do so may corrupt the file and result in an error message. However, as of Outlook 2003, the OST and PST file storage format has become a Unicode variant. This made it possible to store files up to 20GB in size! But that was not the end of the notable improvements: as of Outlook 2010, files can now exceed the 20GB limit. OST and PST file formats can now store up for 50 GB of data. This outstanding performance (when comparing the size of older PST and OST files with newer ones) has also brought more recent problems with OST and PST formats to the table. In addition to Outlook not being able to open older formats, OST and PST files have become more vulnerable and can be easily corrupted. ### Advantages of PST over OST PST files can be moved to local computer while OST files are synced individually using a server. PST file supports uploads to other email services, but OST files cannot be moved to other services unless converted. PST files can be copied up and automatically restored, but the OST still requires server sync. ### Advantages of OST over PST OST syncs automatically, while PST, on the other hand, requires it to be downloaded locally. OST modifications automatically appear on the server. But PST files become a separate entity once downloaded. Your emails/files can be used on other devices without having to download them locally. However, PST is different in that you will need to download emails and files locally before you can access them on other devices. ## Final note I hope you like the guide How to Differentiate in Outlook’s PST/OST Files. In case if you have any query regards this article you may ask us. Also, please share your love by sharing this article with your friends. --- *End of Article*