Maintain Outlook Healthy: How to Eliminate Duplicate PST Files

Microsoft Outlook is one of the most trusted email management tools used by professionals and businesses everywhere. Over time, users can start to notice performance issues, mailbox sizes of an unusually large size, or confusion in storage, all due to duplicate PST files. These duplicate files not only eat away at much-needed disk space, but they can also be a factor in slowing down Outlook operating systems. 

In this article, we're going to explain how to find and eliminate duplicate PST files manually, which can help restore Outlook to an efficient state. Afterward, we will introduce a reliable and trusted automated solution, Outlook Duplicate Remover, which will make the entire process really easy.

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Why Duplicate PST or Duplicate Items Are a Problem

Before we get into solutions, let's examine how duplicate PST sneak in:

• Import / Export problems: Often, it is exporting and re-importing versions of your PST while not paying attention to the "do not import duplicates" settings, which leads to entire folder duplicates.
• Sync problems: When you mix in using cloud sync (OneDrive, Dropbox) with PST files, or just multiple profiles of MS Outlook, duplicates may appear.
• Backup / restore, same old story: Restoring a previous backup over an existing PST can lead to duplicate folder or file(s).
• Errors in rules & add-ins: Duplicate deliveries can also happen due to corrupt Outlook rules, or even an anti-virus email scanner or add-ins, which deliver the same email when it shows up in your inbox.
• Corruption of naming scheme: Outlook can also create its own "PST (hostname)" duplicates, as a file name cannot be overridden if the original name already exists.

So what happens as a result of this? Sluggish performance, giant PST files, and user dissatisfaction. Here is how to clean duplicates up and out of Outlook - first manually, then by using a tool.

Frequently Seen Causes Of Duplicate PST Files

By understanding how duplicate PST files are created, you may be able to avoid them in the future:

• Multiple Imports/Exports - Importing the same PST file more than once and not checking the Do not import duplicates option can cause duplicate PST files.
• Improper Backup Restore - When you restore an older backup, you will then have two of everything in the new backup.
• Outlook Profile Issues - Sometimes, Outlook can not find, or can find issues with, your existing PST file, and it can create a new PST file automatically.
• Conflicts With Synchronizing - When using PST files with cloud services, it can create duplicate PST files when the service restores an earlier version of the PST file.
• Manual Copying - Manually copying and renaming PST files in order to back up PST files can lead to more than one file that is identical and stored in a different folder.

Despite their origin, you can have duplicate PST files. The recommended quantity of duplicate PST files is zero. Even one can create issues in Outlook.

Manual Methods To Eliminate Duplicate PST Files

If you don't want to use a third-party tool, manual methods in Windows and in Outlook are available to discover and delete duplicate PST files. Let's explore both methods.

1. Inspect Outlook Data File Settings

This is the easiest way to locate and remove duplicate PST.

1. Open Outlook.
2. Go to File → Account Settings → Account Settings.
3. Select the Data Files tab and note all open PST files associated with Outlook.
4. Hold on: Locate PST files with similar names or file paths.
5. Highlight the duplication and hit Remove.

You should also be careful to avoid the primary in-use PST. Check the location of a PST file before you remove it.

2. Searching PST Files Manually in File Explorer

Outlook can sometimes store a hidden duplicate PST in your local folders, which is where you may want to locate and handle it as follows:

1. Exit Outlook completely.
2. Go to File Explorer and go to:
3. Sort by Date Modified or Size.
4. Take a look at any file that has the same name, for example:
5. Review their sizes or open them separately in Outlook to ensure duplication.
6. Once you are sure, delete the duplicate PST files or move them to a backup location before deleting.

3. Create a new Outlook Profile

If Outlook opens multiple PST each time you open it, the problem could be that your Outlook has become cluttered. You can fix a hidden PST in your Outlook by creating a new Outlook profile, removing the previous PST:

Steps

1. Close Outlook.
2. Open the Control Panel → Mail → Show Profiles.
3. Click Add and create a new profile, choosing any name.
4. Add your email account again.
5. Only attach the required PST file (the main one).
6. Open Outlook in the new profile.

4. Avoid Duplicates During Import

When you import from another PST file, Outlook will provide you with the option to choose what to do with duplicate items. To avoid any new duplicates:

1. Go to the File tab, and then select Open & Export → Import/Export.
2. Select Import from another program or file → Outlook Data File (.pst).
3. Browse and select the appropriate PST file.
4. Then, when prompted, choose “Do not import duplicates.”
5. Then complete the import.

This small step helps avoid the original duplication of PST.

Limitations of Manual Removal

While manual de-duplication can work for small cases, it can be error-prone or take time to do this for many accounts or large Outlook data files. It is difficult to manually compare two similar PST files, and if you delete the wrong one. Additionally, Outlook does not have any built-in means to identify duplicates based on content within the PST files.

If you want a quicker, safer, and more assured resolution to removing pasted files, use a third-party utility designed for the specific purpose of removing duplicate PST.

Perfect Solution to Eliminate Duplicate PST Files

If you're dealing with a large number of duplicate PST across various mail folders or sorting mailboxes, a manual method quickly becomes impractical. This is the exact use case for a dedicated deduplication software solution, like TrustVare Outlook Duplicate Removal. This tool is used to choose duplicate PST files without needing to install other software or applications. The software quickly detects different duplicate PST files and removes them, while not deleting the original data. It runs on all versions of Windows operating systems, including Windows 11, 10, 8.1, 8, and 7. Eliminate duplicate PST files without intervening. And best of all, you will not need to have additional technical knowledge to run this software.

Detailed Features of The Tool:

• Intelligent PST Finding: Automatically searches and finds duplicate PST files on your computer.
• Batch Mode Ability: Integrates and duplicates PST files together and processes them at once from different PST.
• No Data Loss: Preserves all data integrity when you delete duplicate PST files, including emails, contacts, and settings etc.
• Preview Option: It tells the user the duplicate PST files it found before you have it delete them, for a real confirmation before you delete them.
• Compatibility: Works with all the best Outlook versions (2003-2024 and including Outlook 365)
• User-Friendly: It is a simple design of the software layout; no technical knowledge is required.

Tips to Avoid Duplicate PST Files 

• Try to only have one main PST for every account or data set.
• Make sure your PST files have something meaningful so that you aren't confused in the future.
• Never use a file stored within a directory synced to the cloud as a PST.
• Make it a regular practice to check your Account Settings → Data Files section for unnecessarily added files.
• Always take a backup beforehand for any major cleanup or Outlook configuration change.

Final Thoughts

Duplicate PST files are an unrecognized enemy of Outlook's performance and stability. They take up disk space, confuse you about the correct version, and sometimes even corrupt data. You can delete the few duplicates manually, but as they multiply, more and more of them become unrealistic to delete without support.

Outlook Duplicate Remover is a perfect fit to eliminate duplicate PST fast, accurately, and safely in Outlook. The software gives you the chance to maintain an orderly, clean, and healthy environment while using Outlook.