Best Way to Split Large Outlook PST File – Reliable Approaches

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  • Updated on June 19th, 2023

PST file is the database file created by Microsoft Outlook. Over the years, MS Outlook has rolled out many changes in PST files. Outlook is used by computer users for more than a decade. Due to excessive data, the PST files become large and it is hard to split them into small sizes. Here in this article, there are several measures to split large Outlook PST files into small PST files using manual ways and professional software named Sysinfo PST Split tool.

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We would be covering the following Topics in this article:

  • Types Of PST formats
  • Consequences of Over-Sized PST (If PST maximum data limit is reached or exceeded)
  • Best Solutions to split large Outlook PST file into small files

Split PST file into multiple

Types of PST Formats

The data in MS Outlook is stored in PST file which comes in two formats: ANSI PST and Unicode PST


MS Outlook 2002 and earlier versions create and understand ANSI PST files. It comes with a data storage limit of 2 Gb. This clarifies that we cannot store data of more than 2 GB in ANSI PST files. If the data limit is exceeded, the PST is more likely to face corruption.


MS Outlook 2003 and later versions create PST files, which are in a Unicode format. The maximum data limit in a Unicode PST file is 20 GB. Here as well, if you reach or exceed the maximum database size limit, your Outlook will refuse to work or your PST file may even get damaged.

Consequences of Over-Sized PST

Well, it’s not always the matter that you face issues with your Outlook PST file only when it exceeds the maximum data limit (either ANSI or Unicode PST). Over the last couple of years, I had received many queries from different users across the globe. Common Queries:

  • Outlook PST is Corrupted
  • MS Outlook Slow Response
  • Emails Fail to Send
  • Outlook hangs before closing

So these are the most received queries according to the number I counted. Though the queries are different, there was one common issue I got to know when I talked to them. Every user’s PST file had almost reached or crossed the maximum PST data limit. If your Outlook PST is already corrupted, you can repair the PST file with PST Repair Tool by Microsoft. Reason Behind PST Corruption and other failures All the issues are directly connected to the size of our Outlook PST file. Example: Our windows computers start responding slow if the default drive where the Operating System is installed is low in space. As the PST file contains all the other email data in it except our emails, it is more prone to face issues like what I mentioned above. So, what do you think you should do if your Outlook PST is formatted?

Best Solutions to split large Outlook PST file

You can Split PST files manually or you may also try an automated PST splitter which can easily split your PST file into multiple files or save your data from corruption. Remember, by using these techniques we actually make space in our PST by using multiple methods (PST doesn’t split here). There are three solutions available in your already installed Outlook Version:

  • Archive PST
  • Import and Export
  • Move to Folders

Here I’ll tell you the most reliable and my favorite option I use and recommend others to follow, as archiving also provides us with the backup of our Emails.

How to Archive Emails in MS Outlook to move PST file content and save as a backup

  • In Outlook 2007, Go to file ⇒ Click on the Archive tab (Example Shown in the Image Below)

Split PST files

  • By default “Archive this folder and all subfolders will be selected”, you may also change it to “Archive all folders according to their auto archive settings”
  • You can set up archiving according to the date by changing the date in the “Archive items older than” settings.
  • By default, the archive file path must be C:UsersphillAppDataLocalMicrosoftOutlookarchive.pst
  • You can change the file path where ever you feel like.
  • Click on OK, and the archiving process will start.

Once the archive process is completed, you may delete your emails from the inbox and also keep the archive file as a backup of your email files. Remember you have not split your PST file, it’s just a backup you have taken. Microsoft Outlook doesn’t give any option to split large Outlook PST file. Hence you need to do this using a third-party tool. If so far I was able to deliver a bit of knowledge or a solution for your oversized PST file, I would recommend you use Sysinfo PST Split Tool. Remember this is a suggestion, and do not opt for any tool without prior trial. Create a copy of your PST file and further test this tool on it. If it works for you, then you may surely go for it.


We have discussed solutions to split large Outlook PST file using a manual and automated technique. As an automated solution, we used a third-party utility which is an effective and reliable method as compared to the manual method. So we recommend using the automated solution.

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