Split PST File Split PST File
4.5 · 829 votes

Split PST File into Smaller Parts

Split a large Outlook PST or OST file into several smaller PST parts on your Windows PC. Works offline, without Outlook running, and leaves the original file untouched.

   
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A PST file that grows past a couple of gigabytes starts to drag Outlook down, and near the old 2 GB limit it can corrupt and lock you out of your own mail. Split PST File breaks that oversized archive into smaller PST parts you can open, back up, or share. Choose By Size, By Date, By Folder, or By Sender. The program writes new PST files while your original stays as it was.

How to split a PST file

Add your PST or OST file.
1

Add your PST or OST file

Point the program at one Outlook data file. It reads the folder tree without Outlook open. A closed or disconnected mailbox works fine too.

Pick the folders to include.
2

Pick the folders to include

The folder tree appears on the left with checkboxes. Keep the whole mailbox, or tick only the folders you need.

Choose a split mode.
3

Choose a split mode

Pick one of the four radio options, then set its value. By Size takes a size cap; By Date period takes a period length.

Set a destination and run.
4

Set a destination and run

Choose an output folder and start. Each part lands as its own PST, and a CSV report lists every file with its message count and size.

Why split your Outlook PST

A single overgrown PST causes most Outlook slowdowns. Splitting it removes the cause..

A single overgrown PST causes most Outlook slowdowns. Splitting it removes the cause.

  • Stop freezes and crashes as a PST nears the 2 GB limit.
  • Cut a heavy archive down so a part fits an email or cloud upload.
  • Keep per-year archives for audits, storage rules, or a handover.
  • The source file stays untouched. Every part is written as a new PST.
  • Everything runs on your PC, so the mail never leaves for a server.
   
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Reduce an oversized PST when Compact no longer helps

Outlook's own Compact Now only reclaims empty space, so once a data file is full of mail it barely moves the needle. Splitting carves that heavy file into several smaller PSTs, each small enough to open quickly and back up on its own.

You keep every message, spread across parts you name yourself. Point Outlook at the parts you still use day to day and shelve the rest.

Four ways to split, plus a clean paper trail

Split by size

Set a threshold in MB or GB, 1 GB by default, and the program fills each part up to that cap. It cuts on message boundaries, so an oversized message becomes its own part instead of being split across two files.

Split by date period

Group mail by Year, Month, or Week from the message date. Each period becomes one PST, named like 2023.pst or 2024.pst. Undated items go to their own part.

Split by folder

Send each top-level folder to its own PST. Inbox, Sent, and any archive folder become separate files, with the folder hierarchy inside each part intact.

Split by sender

Route mail into a PST per sender for a legal hold or one person's correspondence. Senders with only a few messages are pooled into one others.pst.

Exclude Deleted and Junk

Leave Deleted Items and Junk out of the split with one checkbox. The parts you keep carry only the mail you want.

CSV summary report

Every run writes a CSV listing each part, its file name, message count, and size. Hand it to a manager or keep it with the backup.

Split PST File
Split PST FileDownload the Split PST File tool and split one big PST into clean, openable parts by size, date, folder, or sender, right on your PC.
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Who splits PST files

IT admins and helpdesk

You inherit oversized mailbox archives and need parts that open fast and back up without timing out. By Folder and By Size do most of that work.

Legal and compliance

For one custodian or one year, By Sender and By Date period pull those messages into their own PST, so nothing extra ends up in the export.

Long-time Outlook users

Years of mail in one file turn slow and risky. Split it into yearly parts and everything stays searchable, while the old giant file stops being a single point of failure.

Split PST File
Split PST File
Price
from $ 29.99
Version
1.7
File Size
8 Mb
Last updated on
03/10/26
System Requirements
  • Windows 11/10/8.1/8/7 (32/64 bit)
  • Intel i3, AMD Ryzen 5 or above
  • 4 GB of RAM or above
  • NVIDIA® GeForce® series 8 and 8M, Intel® HD Graphics 2000, Quadro FX 4800, Quadro FX 5600, AMD Radeon™ R600, Mobility Radeon™ HD 4330, Mobility FirePro™ series, Radeon™ R5 M230 or higher graphics card with up-to-date drivers
  • 1280 × 768 screen resolution, 32-bit color
  • 1 GB of free hard disk space or above

Frequently Asked Questions

Install the program, add your data file, and let it run the split. This PST splitter software reads Outlook data files directly, so Outlook does not have to be installed or open. You can split a mailbox exported from another machine.

Outlook has no split command, so the free routes are manual. You create new PST files by hand and drag folders across, which is slow and easy to get wrong on a large mailbox. The program offers a free trial that processes a sample of your mail, so you can check the result before buying a license.

Yes. By Size is the default mode. You set a cap in MB or GB, and each part is filled up to it. Because the split happens on message boundaries, parts land close to the target rather than exactly on it, and no message is ever split across two files.

Choose By Date period and set it to Year. Each calendar year becomes one PST, named like 2023.pst and 2024.pst. Pick Month or Week for finer archives.

The program reads your source file and writes the parts as separate new PSTs. Everything runs locally, so your mail is never uploaded anywhere.

Years of mail, large attachments, and old ANSI PSTs capped near 2 GB are the usual reasons. Newer Unicode PSTs allow up to 50 GB but get sluggish long before that. Split the file into smaller parts once compacting no longer helps.

No. Split PST File treats the source as read-only. It writes new PST parts into the destination folder you choose and leaves the original file byte for byte the same, so you can always go back to it.

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Author: SoftOrbits (English)
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Avg. rating: 4.5 from 829 votes
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