How to copy Outlook OST files to another computer?

In the realm of email management, Microsoft Outlook stands tall as a reliable companion for millions. However, there are instances when the necessity to transfer an Outlook OST (Offline Outlook Data File) to a different computer becomes apparent. These situations can emerge because of various reasons, be it a hardware upgrade, switching to a new workstation, or simply needing a backup. 

Moving to a new computer is never simple. You have to be careful with your data and ensure everything transfers smoothly without any alterations. Data loss is the most common in such a type of migration. To avoid that; it is advisable to understand the complete procedure better before you move ahead. In this comprehensive guide, we will delve into the intricacies of how to accomplish this task effectively, even in scenarios where the new computer operates on macOS.

Understanding Outlook OST Files

Before we dive into the process, let’s grasp the basics. OST files are primarily used for offline access to your mailbox when connected to Exchange Server. They are profile-specific and aren’t as portable as PST files. However, situations may demand their migration to a new PC, and that is when you may need to convert OST to PST file format.

Methods for Copying an OST File to Another Computer

There could be two possible methods to copy the PST files to a new PC without data loss. One is doing it manually, and the other is using a third-party tool. Let us first learn how we can accomplish the job manually

Note: This procedure applies to users who plan to stick with MS Outlook on their new computer. However; if you intend to use a different application on your new PC, such as Thunderbird, this method won’t be suitable. In that case, you should convert the OST file to the MBOX format and then import the MBOX file into your Thunderbird account.

Method 1: Manually Copy the OST file from old computer to new computer.

Step 1: Find the OST File

  • Open Outlook on your current computer.
  • Click on “File” in the top left corner.
  • Choose “Account Settings,” and then select “Account Settings” again.
  • In the Account Settings window, go to the “Data Files” tab.

You’ll see a list of data files, including your OST file. Make a note of where it is located on your computer.

Step 2: Copy the OST File

  • Close Outlook on your current computer.
  • Use a USB drive, external hard drive, or email/cloud storage to copy the OST file from your current computer to the new one.

Step 3: Set Up Outlook on the New Computer

  • Install and set up Microsoft Outlook on the new computer if you haven’t already.
  • Open Outlook. It will try to create a new OST file for your email account.
  • Before Outlook fully synchronizes with your email server, close it.

Step 4: Replace the New OST File with the Copied One

  • Find the new OST file Outlook created on your new computer. It should be in a similar location to the one on your old computer.
  • Rename the new OST file (e.g., add “_old” to the filename) to keep it as a backup.
  • Copy the OST file you transferred from your old computer into the same location on your new computer.

Step 5: Reopen Outlook

  • Reopen Outlook on the new computer.
  • Outlook should recognize the copied OST file and use it to sync with your Exchange Server mailbox.

Important Notes:

  • This method may not work in all cases, as OST files are linked to specific profiles and Exchange Server setups. It’s often simpler to create a new profile on the new computer and let Outlook generate a new OST file.
  • Ensure you have the necessary permissions to access the OST file on both computers.
  • Always back up essential data before making changes or transferring files.

Method 2: Export OST to PST using Magus OST converter and copy the PST file to New PC

Step 1: Convert OST to PST

  • To make an OST file portable, convert OST to PST format. You can use Magus OST to PST conversion tool for this purpose.
  • Ensure you select a reliable tool that preserves data integrity during the conversion process.

Step 2: Transfer the PST File

  • Once you have the PST file, transfer it to the new computer. Common methods include using a USB drive or a secure file-sharing service like cloud storage or email.

Step 3: Import into Outlook

  • On the new computer, open Microsoft Outlook if it’s in use. If not, you can install it or proceed with alternative solutions as explained below.
  • In Outlook, use the import/export wizard to bring the PST file into your new Outlook profile. This process may vary slightly depending on your Outlook version.

For Mac Users: Importing OST Data

If your new computer is a Mac, and you wish to use Outlook on it, the process remains the same as described above. However, it’s essential to note that if you are using the latest version of MS Outlook on Mac or the free version, importing PST files may not be supported, and the import/export option could appear greyed out. In this case, consider switching back to the legacy Outlook or convert the OST file to OLM format to import the .olm file into your Outlook for Mac.

Now, what if your new computer is a Mac, and you’re not using Outlook but Apple Mail? Let’s address this scenario:

Step 1: Convert OST to MBOX (for Apple Mail)

  • First, convert the OST file to the MBOX format, which is compatible with Apple Mail. Utilize Magus OST to MBOX converter for this task.
  • Ensure that the tool maintains data fidelity during the conversion.

Step 2: Transfer the MBOX File

  • Copy the MBOX file to your Mac using a USB drive or any preferred transfer method.

Step 3: Import into Apple Mail

  • Open Apple Mail on your Mac.
  • Use the import feature within Apple Mail to bring in the MBOX file that contains your Outlook data.


Transferring an Outlook OST file to another computer, whether it’s running Windows or macOS, requires a few critical steps: conversion, transfer, and import. By following these steps, you can ensure that your valuable email data is accessible and ready for use on your new computer, regardless of its operating system or email client.

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