If you’re an Outlook user, then you might be dealing with a corrupt PST file creating duplicate items like emails, contacts, notes, calendar, etc., which is a very frustrating error as these duplicates make your mailbox cluttered, which causes Outlook mailbox full, slows down the performance of Outlook and increases the chance of risk of data loss. In this article, we’ll discover how and why a corrupt PST file creates duplicates and fix it using both manual and automated methods effectively.

Why Corrupt PST File Creating Duplicate in Outlook?

A corrupt PST file is a file where all Outlook data is saved, including all metadata, formatting, and attachments, but has become corrupted and creates duplicates due to many reasons, like:

1. Syncing error

When the file gets corrupted, then Outlook is not able to sync properly with its server, as which result, it leads to Outlook downloading the same emails again.

2. Increased PST files

If you’re using an older version of MS Outlook, then it only has a 2 GB size limit. If you pass this limit, then it causes data corruption, and also in the new version, if files get corrupted, then it will make duplicates.

3. Improper Shutdown

If Outlook crashes while working, then your PST file may not be saved, and when you reopen, it may reload the items or files you saved earlier, which creates duplicates.

4. Virus infection

There’s also a chance that your PST file gets corrupted by a virus attack and makes duplicates of items like emails, contacts, tasks, etc.

Best Methods to Fix Corrupt PST File Creating Duplicates

Solution 1: Repair File Using Built-in Repair Tool

ScanPST.exe is a free in built tool by MS which helps to fix small issues in PST file.

Steps:

1. Close Outlook and search for scanPST.exe in your system.

2. Launch the tool and browse your files (corrupted).

3. Click Start to start the scanning process.

4. Finally, when the scanning process is complete, hit repair.

Note: How to repair Outlook PST file without ScanPST 

Cons:

• It only repairs the files which get damaged, but does not eliminate duplicates.

• It may not be able to work if files get too corrupted.

Solution 2: Manually Deleting Doubles in Outlook

After repairing the PST file, duplicates remain in that file only, so remove them manually.

Steps:

1. Nav to the damaged folder, like the inbox, spam, etc.

2. Sort emails by applying filters like sender, subject, date, etc.

3. Select them by Ctrl+A and remove duplicate emails in Outlook.

Cons:

• It’s a very time-consuming method which takes both time and effort.

• Not a good solution if there are a lot of emails.

There are many limitations when using manual methods, so try to opt for an alternative to this; use an automated tool, which can help you in preventing the drawbacks faced in manual methods.

Solution 3: Use a Professional Software 

If you’re working with many duplicate emails and want a fast, accurate and automated result after repairing a PST file, we recommend using SysTools Outlook Duplicate Remover, which helps us in removing similar items easily.

Key features of this aforementioned tool

• It supports all previous Outlook versions, including Office 365.

• This method bulk removes duplicates, which saves time and effort.

• It provides filters for cleaning duplicates like subject, sender, date, etc.

• Provides dual mode, which accepts PST/OST/BAK files.

• Also, it keeps the data structure and its integrity maintained while removing the process.

Steps:

1. Download and run the professional tool on your system.

2. Click on Add file and folder to upload your files from your operating system.

3. This software offers a Dual mode that is within and across the folders.

4. Choose the location to save the output file

5. Select items to delete in the select item type.

6. Apply filters like name, email ID, number, etc, in specific duplicate criteria.

7. Press Ok to fix Outlook corrupt PST file creating duplicates.

Prevention Tips for PST Corruption & Duplicates

• Avoid the immediate closing of Outlook

• Always and regularly back up your Outlook files.

• Keep your Outlook and installed antivirus updated.

• Archive or delete old messages to free up space for smooth performance.

Conclusion

In this article, we’ve discussed how and why corrupt PST file creating duplicates and how to fix them by using manual and automated methods. MS offers an in-built tool, but it’s not that useful for larger files. If you want the result quicker and accurately, then use the suggested tool above, which will help you in every manner by saving time and effort.