Email Conversion Guide
By To convert Pegasus Mail to Outlook PST, copy the mailbox folder from C:\PMAIL\MAIL, open it in a converter that reads PMM and CNM files, choose PST as the output and run it. The result is one PST with the same folders you had in Pegasus. Open it in Outlook through File, Open & Export, Open Outlook Data File. Pegasus has no PST export of its own, so the only other route is copying mail through an IMAP server folder by folder.
The new PC runs Outlook. The old mail lives in Pegasus. Someone has told you to export a PST, and you have found that Pegasus Mail has no such button. That is the whole reason this page exists.
Below is the direct method that reads the Pegasus files and writes the PST for you, then how to open that PST in both classic and new Outlook. After that comes an honest look at the manual IMAP route, which is free and works, but is slow and loses shape on a big mailbox.
Can Pegasus Mail Export to Outlook PST?
No. Pegasus Mail, David Harris's client that has run on Windows since the early 1990s, keeps every mail folder in a .PMM file, indexed by a .PMI file beside it, and drops each new message into its own .CNM file. It can copy mail to an IMAP server and it can save single messages, but it has no export to Outlook's PST format and never has.
That leaves two ways to convert Pegasus Mail to Outlook. The first reads those .PMM and .CNM files straight off the disk and writes a PST, which is what the steps below do. The second pushes every folder up to an IMAP account and lets Outlook download it, covered further down. One is a conversion, the other is a long copy job.
How Do I Convert Pegasus Mail to PST?
These four steps go from the Pegasus mailbox folder to a PST open in Outlook. Univik Pegasus Converter does the middle two on its own, with no Pegasus Mail or Outlook needed on the converting PC.
Take a copy of the Pegasus mailbox folder
Close Pegasus Mail and copy the mailbox folder to a place you can work from. On a standard install it is C:\PMAIL\MAIL, and inside it a folder named after the user holds the .PMM folder files, their .PMI indexes and the loose .CNM new-mail messages. Copying keeps the original safe and lets you convert on any Windows PC, even one that never had Pegasus on it.
Open the folder in Univik Pegasus Converter
Install the converter from the free download and choose Open. Either browse to the copied mailbox folder, or, on the PC where Pegasus is set up, pick one of the accounts the Open menu lists, including IMAP and POP3 ones. The folder tree loads as it looked in Pegasus, with New Mail, sent items and every folder you made. Tick only the folders you want.
Choose Outlook PST as the output
Pick PST from the save formats, choose where the file goes and start the run. Every message keeps its sender, recipients, subject, date and attachments. The folder layout is written into the PST as it stood. The free trial writes a few messages from each folder so you can open the result and check it before buying a licence.
Open the PST in Outlook
In classic Outlook go to File > Open & Export > Open Outlook Data File and select the PST. In new Outlook go to Settings > Files > Outlook Data Files and choose Add file, which needs classic Outlook installed alongside. The Pegasus folders appear as a new data file in the folder pane, ready to read, search or drag into your main mailbox.
How Do I Open the PST in Outlook?
The PST is a normal Outlook data file, so Outlook opens it the same way it opens any archive. In classic Outlook use File > Open & Export > Open Outlook Data File, browse to the PST and click OK. It appears at the bottom of the folder pane under its own name, and you can read, search and drag folders from it into your main mailbox.
In new Outlook go to Settings > Files > Outlook Data Files and choose Add file. Microsoft notes that this needs classic Outlook installed alongside, in the same 32-bit or 64-bit build. Either way, keep the PST under the default 50 GB limit that Outlook 2010 and later place on Unicode PST files. A typical Pegasus mailbox is a small fraction of that.
What About the Manual IMAP Route?
Before converters existed, the PMAIL community's answer to moving Pegasus Mail to Outlook was IMAP. Set up the same IMAP account in Pegasus Mail and in Outlook, then in Pegasus copy each folder up to the server. Outlook syncs the account and the mail comes down on the other side. It costs nothing beyond a mailbox with enough room.
The catches are real. It goes one folder at a time, so a mailbox with sixty folders is an evening's work. Every message travels through the server, which matters if the mail is private or the connection is slow. Servers often rename or flatten nested folders, and some drop message dates. And the whole plan depends on Pegasus Mail starting, which is not a given on an old PC. It is a fair route for a handful of folders and a poor one for twenty years of mail.
We tested the converter against a Pegasus install with both IMAP and POP3 accounts set up. Every account loaded from the Open menu, converted to PST with no errors and opened in Outlook with the folders in the right places.
Pegasus Mail to PST: Which Route?
Both get mail into Outlook. The table shows where they part ways.
| Question | IMAP copy | Direct PST conversion |
|---|---|---|
| Needs a mail server | Yes, an IMAP account with space | No |
| Works if Pegasus will not start | No | Yes, it reads the files |
| Whole mailbox in one go | No, folder by folder | Yes, one run |
| Folder layout kept | Often changed by the server | Yes |
| Mail leaves your PC | Yes, through the server | No |
| Time for a big mailbox | Hours | Minutes |
| Cost | Free | Free trial, then a licence |
Univik Pegasus Converter takes the PMM, CNM and PMI files and produces an Outlook PST with the folder tree kept, plus MBOX, EML, PDF and direct upload to Office 365 or Gmail if you need them. No Pegasus Mail and no Outlook required to run it.
Windows 7 to 11 · runs on your PC, nothing uploaded · the trial saves a few messages per folder
The short version
- Pegasus Mail has no PST export, so the mail has to be converted or copied through IMAP.
- Copy C:\PMAIL\MAIL, open it in Univik Pegasus Converter, pick PST and run. Folders are kept.
- Open the PST in classic Outlook under File then Open & Export, or in new Outlook under Settings then Files.
- Outlook 2010 and later allow 50 GB per PST, far more than a Pegasus mailbox needs.
- The IMAP route is free but slow, folder by folder and dependent on Pegasus starting.
Convert Pegasus Mail to PST, free trial
Pegasus Mail to Outlook Questions
About This GuideWritten and tested by Leena Taylor Paul for Univik, which has built Windows file and email tools since 2013. The conversion was run against a live Pegasus Mail install with IMAP and POP3 accounts configured, and the Outlook steps and PST size figures were checked against Microsoft's own support pages. Updated 22 September 2026. Questions about a specific mailbox? Support is a click away below.
Sources: Microsoft: open and close Outlook Data Files · Microsoft Learn: PST size limits · Univik Pegasus Converter page