How to Safeguard Outlook Performance with Efficient Management of Large PST Files

Updated On - January 15, 2024 by Nasir Khan |

Reading Time: 7 minutes

Today in this blog, we explain How to Resolve Outlook Performance Issues with Large PST Files Size. How to fix this error in an efficient manner. Go ahead.

The moment your Outlook PST file size increases, the Outlook starts lagging, starts causing abruption or pause while sending, receiving, or deleting emails. In such a behavior, you must try to reduce the Outlook PST file size.

Outlook users may encounter message as:

Resolve Outlook Performance issue with Large PST Files Size

Outlook performance Issues caused by Large PST Files size

Large-sized PST file can cause several issues such as:

  • PST file corruption due to data integrity
  • Outlook performance issues
  • Outlook errors such as Not Responding, Outlook crash, etc.

Six Simple Methods to Fix Outlook Performance Issues with Large PST Files

1st method: Configure Outlook PST file size limit

Microsoft Outlook users can set the PST file size limit by registry modification. Outlook user can configure PST file size limit by modifying the registry entry size value.

2nd method: Remove duplicate emails from Outlook PST file

Duplicate emails also result in oversized PST file. Removing duplicate emails can help resolve the Outlook performance issue. Reasons that may lead to duplication of emails include –

  • Incorrectly configured Rules
  • Short Send/Receive intervals
  • Improper Mailbox settings
  • Incorrect Account setup
  • Third-party anti-virus scanner

3rd method: Manual Steps to reduce the large size of PST files

To improve the performance of MS Outlook, you must reduce the Outlook mailbox size firstly by deleting unwanted email items and then compacting the Outlook PST files. To achieve this, perform the steps as discussed below:

  • Launch Microsoft Outlook application.
  • Right-click on the Deleted Items folder and then click Empty Folder. 2
  • Or select the folder that is no longer needed, in the Home menu, click the Cleanup In the drop-down menu select any of the three options (Clean Up Conversation, Clean Up Folder, and Clean Up Folder & Subfolders) to delete unwanted files and duplicate data from the folder. 3
    • Clean Up Conversation: This option deletes duplicate or unimportant email messages from the selected folder.
    • Clean Up Folder: This option deletes the message(s) from a certain folder.
    • Clean Up Folder & Subfolders: This option deletes the folder that is not required.
  • Click File > Account Settings > Account Settings. 4
  • Under the Data Files tab, choose your Outlook data file and click Settings. 5
  • In the Outlook Data File dialog box, click Compact Now > click OK. 6

On following the above steps, your Outlook PST file will be compacted.


4th method: Archive your Outlook Data

Archive old Outlook mailbox data to keep your mailbox from filling up and reaching its maximum size. Move the old items you want to keep to an archive i.e., a separate Outlook Data File (.pst). The archive can be accessed whenever needed.

Note: The Archive and AutoArchive options might not be available in your Outlook mail if your profile connects to an Exchange Server.

Archiving Data in Outlook 2013 / 2016 / 2019

  1. Launch MS Outlook application.
  2. Click File > Info.
  3. In Outlook 2013, click Cleanup Tools > select Archive.
  4. In Outlook 2016, click File > Info > Tools > Clean up old items. 8
  5. Select Archive this folder
  6. Under Archive items older than, select a date.
  7. Click Browse to select the folders you need to archive.
  8. Select the checkbox Include items with “Do not AutoArchive” checked to archive individual items that are excluded from automatic archiving.
  9. Click OK. 9

#Archiving Data in Outlook 2010

  1. Launch MS Outlook application.
  2. Click File > Cleanup Tools > Archive.
  3. Select Archive this folder and all subfolders and then select the folder that you want to archive.
  4. For Archive items older than specify a date.
  5. Click Browse to specify a location for the archived file.
  6. Select the checkbox Include items with “Do not AutoArchive” checked to include all items that might be individually marked to be excluded from automatic archiving
  7. Click OK.

Archiving Data in Outlook 2007

  1. Launch MS Outlook application.
  2. Click File > Archive.
  3. Select Archive this folder and all subfolders
  4. Specify a date for Archive items older than.
  5. Click Browse to specify the location for saving the archived file under Archive file.
  6. Select the checkbox Include items with “Do not AutoArchive” checked if you want to override a previous setting to not automatically archive specific items.

5th method: Import/Export Process

Import/Export Wizard allows reducing Outlook PST file size. This method does not split the PST file but takes a backup of the old data and transfers them into a new PST file. Using this method, you can manually create smaller PST files segregating the old and new data or move mailbox data from one PST file to the other.

  1. Launch MS Outlook application.
  2. Click File > Account Settings > Account Settings. 10
  3. Click Data Files > Add. 11
  4. Enter a name for the PST file. Type the Outlook data file as “.pst” > click OK to create a new PST.

The new PST file will be visible under Data Files.

  1. Click File > Open & Export > Import/Export. 12
  2. In Import and Export wizard, select Export to a File > click Next. 13
  3. In Export Outlook Data File wizard, select Outlook Data File (.pst) > click Next. Safeguard Outlook Performance
  4. In Export Outlook Data File wizard, choose the required folder to export and select option Include subfolders. 15
  5. Click Browse to specify a location to save the exported file.
  6. Select Do not export duplicates items
  7. Click Finish. Efficient Management Of Large PST Files

Limitations with Manual Steps

  • A time-consuming process.
  • Chances of data loss.
  • Manual method doesn’t work if PST file is corrupted due to oversize.
  • Not applicable for very large PST files.

6th method: An Alternative Solution to fix Large PST file size issue

Use professional third-party Regain PST Splitter to split large or oversized Outlook PST file into smaller PST files. The tool maintains the email properties and folder hierarchy while performing the PST split process. The utility even supports splitting password-protected Outlook PST files. The tool supports both Outlook ANSI and Unicode formats for splitting PST files.

Free Download100% Secure Buy NowPrice: $29

The tool offers three different splitting options –

  • Split by Size
  • Split by Date
  • Split by contain words – To, From, CC, BCC, and Subject

Fully compatible with all versions of MS Outlook and Windows operating systems, the PST Splitter tool offers self-descriptive graphical user interface that makes PST file splitting process an easier process for non-technical users. The available free demo version allows users to check its capabilities before purchase.

Just 5 steps and you are done with PST Split

  1. Launch PST Splitter software.
  2. Select the PST file that you want to split in smaller PST files.
  3. Split among the available options to split Outlook PST file.
  4. Select destination path to save split PST file.
  5. Click Next to complete the split process.


Large-sized Outlook PST files results in low performance of the Outlook application. Thus, it becomes the need of the hour to manage the large-sized PST files, either split them in small PST files or reduce the size of PST files by compacting them. This article discusses manual steps for splitting Outlook PST files. Since manual steps has some limitations, we highly recommend using a professional PST Splitter tool to split large-sized PST files. The free demo version is available to let users check the capability of the software before purchasing the licensed version.

Frequently Asked Questions

Ques1. I have a PST file of 60 GB, and I can access it easily on Outlook, but now I am experiencing degradation in Outlook’s performance; is it a sign of oversized PST?
Ans. There could be multiple issues due to the oversized Outlook PST file, and slowing down Outlook’s performance is a common one. If you are facing these symptoms, then it is recommended to split the PST file.

Ques2. What is an ideal size for the PST file, as Microsoft has recommended a 50 GB upper limit?
Ans. However, Microsoft has recommended a 50 GB upper size limit but still, we will suggest keeping below 40 GB. There are chances that you will not face issues up to 60-70 GB, but it is simply a risk with your email data.

Ques3. Does this tool support all sizes of PST files for splitting purposes as my Outlook is unable to open a PST file that is much oversized?
Ans. Yes, this tool can easily add and open a PST file that is oversized. You can easily set the size for the resultant PST file, and the tool will split it accordingly.

Ques4. I want to create a single PST file for every year; is it possible to split the PST file based on the year, like one for 2021, one for 2022, and so on, using the above-described Regain PST Splitter?
Ans. It is a practical requirement of users; hence this option is present in the Regain PST Splitter. You can easily create individual PST files using the PST split option.

Author: Nasir Khan

I am Nasir Khan from India, working as a Content Developer in Regain Software. Here I am writing about our products and their updates. And writing some free solutions from converting emails or Cloud Migration process. We have tools like Email Converter, Emails backup and Cloud migration.

One thought on “How to Safeguard Outlook Performance with Efficient Management of Large PST Files”

  1. Avatar Betty Chambers says:

    I’ve been having trouble with my PST files for a while, and this article was a great help in understanding the issue and how to deal with it. I’m glad I found this article!

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