Ost Files vs Pst Files: [Understanding the Differences in Outlook]

Last Updated on May 15, 2023 by Amit Bansal

ost-Files vs pst files

When it comes to managing our email accounts in Outlook, we may come across two types of files: PST and OST.

These files are used to store our emails, contacts, and calendar items. Although both of them serve the same purpose, there are some differences between them that we need to be aware of.

PST stands for Personal Storage Table, and it is a file format used by Microsoft Outlook to store our emails, contacts, and other data on our computer’s hard drive.

On the other hand, OST stands for Offline Storage Table, and it is used to store a copy of our mailbox data on our computer so that we can access it even when we are not connected to the internet.

One of the main differences between PST and OST files is that PST files are used for actual storage, while OST files are used for cached storage.

This means that any changes we make to an OST file are automatically synchronized with the email server the next time we connect to the internet.

PST files, on the other hand, are not synchronized with the email server, so any changes we make to them are only available on our computer.

Understanding PST Files and OST Files

What are PST files?

Personal Storage Table (PST) files are used by Microsoft Outlook to store emails, contacts, tasks, and other data.

PST files are saved on your computer’s hard drive and can be easily backed up, imported, or exported.

They are commonly used for POP and IMAP email accounts and can be accessed even when you are offline.

What are OST files?

Offline Storage Table (OST) files are used by Microsoft Outlook to store a local copy of your mailbox data from an Exchange email server.

OST files allow you to work offline and synchronize any changes you make with the email server when you connect to the internet.

Unlike PST files, OST files cannot be easily backed up, imported, or exported.

They are encrypted and can only be accessed through the Outlook profile that created them.

Differences between PST and OST files

The main difference between PST and OST files is that PST files are used for actual storage and OST files are used for cached storage.

PST files are saved on your computer’s hard drive and can be easily backed up, imported, or exported.

They are commonly used for POP and IMAP email accounts and can be accessed even when you are offline.

OST files, on the other hand, are saved on your computer’s hard drive and are used to store a local copy of your mailbox data from an Exchange email server.

They allow you to work offline and synchronize any changes you make with the email server when you connect to the internet.

Another difference between PST and OST files is that PST files can be easily imported and exported to other Outlook profiles or computers, while OST files can only be accessed through the Outlook profile that created them.

If you need to move your mailbox data to a new computer or Outlook profile, you will need to create a new OST file by synchronizing your mailbox data with the email server.

Additionally, PST files can become corrupted if they are not properly backed up or if they exceed their size limit.

OST files, on the other hand, are less prone to corruption because they are synchronized with the email server and can be easily restored if they become corrupted.

In summary, PST files are used for the actual storage of mailbox data and can be easily backed up, imported, or exported, while OST files are used for cached storage of mailbox data from an Exchange email server and can only be accessed through the Outlook profile that created them.

Working with PST Files

When it comes to managing your Outlook data files, PST files can be a lifesaver. Here are some things to keep in mind when working with PST files.

Creating a PST file

To create a PST file in Outlook 2021 or 2019, follow these steps:

  1. Click on the File tab in the top left corner of the Outlook window.
  2. Select Account Settings, and then click on Account Settings again.
  3. In the Account Settings window, click on the Data Files tab.
  4. Click on the Add button.
  5. Choose the type of PST file you want to create and give it a name.
  6. Select the location where you want to save the PST file.
  7. Click on OK to create the PST file.

Importing PST to Outlook

To import a PST file into Outlook 2021 or 2019, follow these steps:

  1. Click on the File tab in the top left corner of the Outlook window.
  2. Select Open & Export, and then click on Import/Export.
  3. In the Import and Export Wizard, select Import from another program or file, and then click on Next.
  4. Select Outlook Data File (.pst), and then click on Next.
  5. Choose the PST file you want to import and select the options you want to use.
  6. Click on Finish to complete the import process.

Exporting PST from Outlook

To export a PST file from Outlook 2021 or 2019, follow these steps:

  1. Click on the File tab in the top left corner of the Outlook window.
  2. Select Open & Export, and then click on Import/Export.
  3. In the Import and Export Wizard, select Export to a file, and then click on Next.
  4. Select Outlook Data File (.pst), and then click on Next.
  5. Choose the data you want to export and select the options you want to use.
  6. Select the location where you want to save the PST file.
  7. Click on Finish to complete the export process.

Managing PST files

If you need to manage your PST files, here are some things to keep in mind:

  • PST files can be used to archive old emails or to move emails to a new computer.
  • PST files can be used with both Exchange accounts and IMAP accounts.
  • It’s important to regularly back up your PST files to avoid losing important data.
  • Large PST files can slow down Outlook, so it’s important to keep them organized and to regularly clean them up.
  • When moving to a new computer or to Office 365, you can easily import your PST files into Outlook.

Working with OST Files

Outlook uses OST (Offline Storage Table) files to store a local copy of your mailbox data from an Exchange Server. In this section, we will discuss how to create, import, export, and manage OST files.

Creating an OST File

To create an OST file in Outlook, you need to configure your email account with Exchange Server.

When you configure your account, Outlook will automatically create an OST file to store a copy of your mailbox data.

The size of the OST file depends on the amount of mailbox data you have, and the maximum size of an OST file in Outlook 365 is 50 GB.

Importing OST to Outlook

If you have an existing OST file that you want to use in Outlook, you can import it by following these steps:

  1. Open Outlook and go to File > Open & Export > Import/Export.
  2. Select “Import from another program or file” and click Next.
  3. Select “Outlook Data File (.pst or .ost)” and click Next.
  4. Browse to the location of the OST file and select it.
  5. Choose the option “Replace duplicates with items imported” and click Next.
  6. Select the items you want to import and click Finish.

Exporting OST from Outlook

If you want to export your mailbox data from an OST file to a PST (Personal Storage Table) file, you can do so by following these steps:

  1. Open Outlook and go to File > Open & Export > Import/Export.
  2. Select “Export to a file” and click Next.
  3. Select “Outlook Data File (.pst)” and click Next.
  4. Select the items you want to export and click Next.
  5. Browse to the location where you want to save the PST file and click Finish.

Managing OST Files

You can manage your OST files in Outlook by compacting them, deleting them, or moving them to a different location.

It is recommended to password-protect your OST files to prevent unauthorized access.

If your OST file is corrupt, you can use a tool like Stellar Converter for OST to repair it and recover your mailbox data.

It is also possible to make your OST file portable by copying it to a USB drive or other removable storage device.

However, keep in mind that password-protected and corrupt OST files cannot be copied or moved.

Overall, managing OST files in Outlook is a straightforward process that can help you access your mailbox data offline and keep it secure.

Differences in Usage

When to use PST files

We use PST files in Outlook when we want to store our emails, contacts, and other data on our computer instead of on the email server.

This can be useful when we have limited storage space on the server or when we want to keep a backup of our important data.

PST files are also useful when we want to access our data offline, without an internet connection.

Another use of PST files is for archiving old emails. We can create an archive PST file and move old emails to it, freeing up space in our primary PST file.

We can also set up Autoarchive to automatically move old emails to the archive PST file, keeping our primary PST file organized and uncluttered.

When we need to back up or restore our Outlook data, we can use the PST file as a backup.

We can copy the PST file to an external hard drive or cloud storage to keep it safe in case of a computer crash or other disaster.

When to use OST files

We use OST files in Outlook when we need to access our data from multiple devices or when we want to work offline.

OST files are synchronized with the email server, so any changes we make to our data on one device are reflected on all other devices.

This makes OST files useful for people who use Outlook on their desktop computers, laptop, and mobile device.

When we work offline, any changes we make to our data are saved to the OST file.

When we go back online, the changes are synchronized with the email server. This means we can continue working even when we don’t have an internet connection.

Like PST files, OST files can also be used for backup and restore. When we back up our computer, the OST file is included in the backup.

If we need to restore our Outlook data, we can restore the OST file along with the rest of our data.

Conclusion

In conclusion, understanding the differences between OST and PST files is crucial for any Outlook user.

While both files serve similar purposes, they are used in different scenarios and have distinct features.

OST files are primarily used for offline access to emails, contacts, and other mailbox items, while PST files are used for archiving and backing up mailbox data.

OST files are automatically created when you set up an Exchange account in Outlook, while PST files need to be manually created by the user.

Another key difference between OST and PST files is that OST files are encrypted with a MAPEntryID GUID key and require authentication from the linked MAPI profile.

This means that OST files cannot be accessed or imported into any other Outlook profile. On the other hand, PST files are importable and can be easily accessed through any Outlook profile.

It is important to note that both OST and PST files can become corrupted or damaged, leading to data loss.

In such cases, it is recommended to repair the files using the built-in repair tool in Outlook or third-party tools.

Overall, understanding the differences between OST and PST files can help you better manage your mailbox data and ensure that your data is secure and accessible.

We hope this article has provided you with a comprehensive understanding of the differences between OST and PST files in Outlook.

Frequently Asked Questions

Here are some common questions people have about Outlook data files:

What is the difference between an OST file and a PST file?

An OST file is an offline Outlook data file that is created when you use Outlook with Exchange Server.

A PST file is a personal folder file that stores your Outlook data on your computer. The main difference is that an OST file is synchronized with the Exchange Server, while a PST file is not.

Can I convert an OST file to a PST file?

Yes, you can convert an OST file to a PST file using a third-party tool. However, it is important to note that this process can be complicated and may result in data loss.

It is recommended that you back up your data before attempting to convert an OST file to a PST file.

How do I repair a damaged OST or PST file?

You can repair a damaged OST or PST file using the Inbox Repair tool (scanpst.exe) that comes with Outlook. This tool scans the file for errors and attempts to repair them.

If the tool is unable to repair the file, you may need to use a third-party tool or restore the file from a backup.

What is the maximum size of an OST or PST file?

The maximum size of an OST or PST file depends on the version of Outlook you are using. In Outlook 2010 and later versions, the maximum size of a PST file is 50 GB.

In Outlook 2007 and earlier versions, the maximum size of a PST file is 20 GB. The maximum size of an OST file is also 50 GB in Outlook 2010 and later versions.

Can I access my Outlook data files from another computer?

Yes, you can access your Outlook data files from another computer if you copy the files to a portable device or use a cloud storage service.

However, it is important to note that if you access your data files from multiple devices, you may experience synchronization issues.

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Amit Bansal

Hello, my name is Amit Kumar Bansal, and I am the founder of MailSmartly.com. Through this blog, I focus on Microsoft Outlook, offering insightful and informative content. Additionally, I produce educational videos on YouTube to further enhance the understanding of my audience. visit my YouTube Channel

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