Merge PST Files Tool for Outlook

Download Merge PST Files Tool for Outlook

Merge PST Files Tool for Outlook combines PST and OST files from old laptops, yearly archives and former colleagues into one new Outlook data file.

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Reads PST and OST files directly, no Outlook profileOutput is a new Unicode PSTFree trial merges a sample, up to 100 emails

Merge PST Files Tool for Outlook Screenshot.

Outlook's Import wizard: one PST per pass

For two small files, Microsoft's Import and Export wizard does the job.

Built-in way

Empty PST plus the Import wizard

Create an empty data file in Outlook, then import every old PST into it with "Do not import duplicates" selected.

Outlook has to be installed and running
The wizard takes one file per pass, so four files means four passes
Every pass asks again where to put the imported mail

Merge PST Files Tool

All of it in one run

Add every old PST in one go, say how they should join and start once.

Copies are caught between any two sources, not only against the target
Your working Outlook mailbox is not touched

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Which PST came from which computer?

After a few computer moves most people have a drive with Outlook.pst, Outlook (1).pst and backup.pst on it, and no idea anymore which mailbox each one was. Merge PST Files Tool lets you keep that origin visible after the merge, so a message from the old work PC is still found under the old work PC. When origin does not matter, everything goes into one shared tree.

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Read each thread once

A laptop archive from 2019 may share conversations with the desktop PST, leaving you with the same reply two or three times. Merge PST Files Tool can skip those repeats and report how many it skipped.

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OST from old profiles goes in too

Add .ost files alongside .pst files in Merge PST Files Tool, including mail stored only in an old PC's offline cache.

A fresh Unicode PST called Merged.pst

Unless you change Save to, the new file goes next to the first source in the list. If Merged.pst is already there, you choose overwrite, rename or skip.

Every source is opened before writing

The program opens every source before copying any messages. A mistyped path or damaged PST stops the run with "The files could not be merged", before it processes the other six files. Damaged files need repair separately.

Stop leaves no half-written file

The new PST is written under a temporary .partial name and renamed only at the very end. Press Stop and there is no output file to clean up.

Big archives without memory spikes

The program writes messages in portions of 2000. Memory use stays at one portion, regardless of file count or archive size.

Empty mail folders keep their place

An empty folder such as Projects 2018 stays in the same place in Merged.pst's hierarchy.

Merge mode and the duplicate switch

Choose your folder layout and whether to skip duplicates before you start.

One Inbox, one Sent Items

Inbox from five PST files becomes a single Inbox, Sent Items joins Sent Items, and so on down the tree.

Default

Best for one mailbox over years

Use it when every source was the same address at different times.

A folder per file

Each top-level folder takes the source file's name without its extension. Its Inbox and subfolders stay as they were.

Same names get a number

Two files both called mail.pst from different drives show up as mail and mail (2). Nothing gets overwritten.

What counts as the same email

Subject, sender address and message text must match. Re:, Fw: and Fwd: in front of the subject are ignored. Date and recipients are not compared.

The list order decides

The program checks for duplicates across files and within each file. It keeps the first copy in list order, so put your most trusted file at the top.

Where it can misfire

Newsletters or automatic reports with the same subject and the same text from the same sender are treated as one message, even when sent on different days. For such archives leave the switch off.

The duplicate option starts switched off every time you open the program.

How to download and use the Merge PST Files Tool for Outlook

Download and add the files

Download Merge PST Files Tool from this page, run setup and click Add files or Add folder. Select the .pst and .ost files you want. Use Remove to take a file out of the list.

Choose the merge mode

Merge same-name folders gives one shared tree. Each file as its own top-level folder keeps the files apart.

Set duplicates and the target folder

Switch the duplicate check on if your archives overlap. Check the Save to folder.

Open Merged.pst in Outlook

The final message reports how many emails and files went into Merged.pst. Open it in classic Outlook as an Outlook data file. We open your source files read-only, leaving them unchanged.

Where your PST files come from

A new laptop and three old PST files

Merge the three PST copies on your USB stick into one file to back up.

Empty desk of a colleague who left the office.

A colleague left, his OST and archives stayed

A colleague's two old archives and the PST from his last PC land on the office helper's desk. Merge them with a separate branch per source, and whoever inherits his job finds the whole history together.

archive.pst, archive 2019.pst, archive 2021.pst

Join ten years of one person's mail in the default mode to get one continuous history.

Before the move to Microsoft 365

Seven PST files mean seven uploads to prepare and check. Merge PST files first and hand over one file.

What the free trial merges

Run the trial on your own files and open the result in Outlook before you decide.

Feature	Free trial	Full license
Emails written to Merged.pst	A sample: all if 20 or fewer, else 10 %, up to 100	Every email
Merge same-name folders	✓	✓
Each file as its own top-level folder	✓	✓
Remove duplicates while merging	✓	✓
PST and OST in one list	✓	✓
The sample is taken in list order, so the first files in the list get into the trial result first.	Download	Buy now From $ 29.99

Buy now

From $ 29.99

Download

The sample is taken in list order, so the first files in the list get into the trial result first.

Merge PST Files Tool for Outlook

Price

from $ 29.99

Version

3.3

File Size

8 Mb

Last updated on

07/08/26

Trial merges a sample: every email up to 20, otherwise 10 % of them, at most 100.

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

How can I merge multiple PST files into one?

Add your files to one list to create Merged.pst in one run. Outlook's Import and Export wizard takes one file at a time.

Can I bring old PST archives from different computers together?

Copy the PST files from each computer to one drive and add them to the list. Choose Each file as its own top-level folder to keep their origins visible. If two are called Outlook.pst, the second becomes Outlook (2).

Will folders from each file be combined or kept apart?

Choose Merge same-name folders for one shared Inbox, or Each file as its own top-level folder to keep sources separate under their filenames.

Can I still use a PST file with Microsoft 365?

Classic Outlook included with Microsoft 365 opens Merged.pst, a normal Unicode PST, as an Outlook data file. For the new Outlook for Windows, check that your version opens PST files before you rely on it.

Will I end up with duplicate emails?

Not if you tick the duplicates option on the Options step. That is how you merge PST files without duplicates: every copy after the first one is skipped, and at the end the tool reports how many. Without the switch all messages go in, repeats included.

Do contacts and calendars come along?

The program copies email only. Export contacts, calendars and tasks separately from Outlook if you need them.

How do I move an Outlook PST file to another computer?

Close Outlook before copying the .pst to the new PC on a USB stick or over the network. Attach it in classic Outlook from the File menu. For several old files, merge them into Merged.pst before copying.

Download Merge PST Files Tool for Outlook

Outlook's Import wizard: one PST per pass

Empty PST plus the Import wizard

All of it in one run

Which PST came from which computer?

Read each thread once

OST from old profiles goes in too

A fresh Unicode PST called Merged.pst

Every source is opened before writing

Stop leaves no half-written file

Big archives without memory spikes

Empty mail folders keep their place

Merge mode and the duplicate switch

One Inbox, one Sent Items

Best for one mailbox over years

A folder per file

Same names get a number

What counts as the same email

The list order decides

Where it can misfire

How to download and use the Merge PST Files Tool for Outlook

Download and add the files

Choose the merge mode

Set duplicates and the target folder

Open Merged.pst in Outlook

Where your PST files come from

A new laptop and three old PST files

A colleague left, his OST and archives stayed

archive.pst, archive 2019.pst, archive 2021.pst

Before the move to Microsoft 365

What the free trial merges

Frequently Asked Questions

How can I merge multiple PST files into one?

Can I bring old PST archives from different computers together?

Will folders from each file be combined or kept apart?

Can I still use a PST file with Microsoft 365?

Will I end up with duplicate emails?

Do contacts and calendars come along?

How do I move an Outlook PST file to another computer?

Related email and Outlook tools

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