Windows Upgrade Guide
By To move Pegasus Mail from Windows XP or 7 to Windows 11, close Pegasus on the old PC and copy the entire C:\PMAIL folder onto a USB drive, or pull the hard drive and read it through a USB adapter if the PC will not boot. Network sharing fails because XP only speaks SMB1, which Windows 11 disables. Paste the folder to C:\PMAIL on the new PC, not under Program Files. Then install Pegasus Mail 4.91 into that folder: the installer upgrades in place and keeps the MAIL folder. Start Pegasus, confirm the folders under Help, About, Info and sign Gmail accounts in again with OAuth2. A 16-bit 3.x Pegasus cannot run on Windows 11, but its mailbox is read by 4.91 after the same steps.
A surprising number of Pegasus installs are still on Windows XP or Windows 7, on a machine kept alive for exactly this reason. Pegasus has been maintained the whole time, and the version released in August 2025 supports Windows 7 through Windows 11, so there is no reason to keep the old box running once the mail is across. The move has three parts: identify what you have and get the folder out. Then bring the program up to date around it.
The mistakes are always the same two. People try to copy over the network and find the old PC invisible, or they install the new Pegasus into Program Files and open it to an empty mailbox. Both are covered below along with the fix for a PC that no longer boots.
Does Pegasus Mail Run on Windows 11?
Yes. The current release is Pegasus Mail 4.91 from August 2025, and pmail.com lists its platform as Windows 7 or later including Windows 10 and 11. It is a 32-bit program, winpm-32.exe, and Windows 11 runs 32-bit programs as a matter of course. Older 4.x releases from the XP years run too, though 4.91 is the one to install because it adds the OAuth2 sign-in Gmail now requires and fixes twenty years of small things.
The one edition that does not run is the 16-bit Pegasus, winpmail.exe, whose last release was 3.12b in November 1999. Windows 11 ships only as a 64-bit system and 64-bit Windows has never included the layer that ran 16-bit programs. If that is what the XP machine has, do not try to copy the program across. Copy the mailbox, which 4.91 reads, and install 4.91.
How Do I Move Pegasus Mail from XP or 7 to Windows 11?
Five steps. The first two happen on the old PC or its drive, the rest on Windows 11.
Find out which Pegasus you are running
On the XP or Windows 7 machine open Pegasus and choose Help > About Pegasus Mail. Anything in the 4.x line is the 32-bit program, winpm-32.exe, and Windows 11 runs it. If the folder holds winpmail.exe and About shows a 3.x version, that is the 16-bit edition last released in 1999. Windows 11 is 64-bit only and cannot start 16-bit programs, so that copy will not run, but its mailbox files are still readable by 4.91. Note the version and the install path, which is usually C:\PMAIL.
Get C:\PMAIL off the old computer
Close Pegasus. Copy the whole C:\PMAIL folder to a USB stick or an external drive, with every sub-folder. Do not rely on a network share: Windows XP speaks only the SMB1 protocol, which Windows 11 leaves switched off, so the old PC will not appear in the new one's network view. If the old machine no longer boots, take the hard drive out, connect it through a USB adapter and copy PMAIL from it. When Windows 11 says you do not have permission to access a folder on that drive, click Continue and it grants it.
Copy the folder to C:\PMAIL on Windows 11
Paste the copied folder so it becomes C:\PMAIL on the new PC, at the root of the drive. Keep it out of Program Files: Windows 11 protects that tree and redirects writes from older programs, which is the cause of most Pegasus start-up trouble on new installs. Same path also matters because Pegasus stores its home mailbox location in PMAIL.INI, and a folder that moved to a different drive letter has to be pointed at by hand.
Install Pegasus Mail 4.91 over the copied folder
Download Pegasus Mail 4.91 from pmail.com, the release of August 2025 that supports Windows 7 through 11. Run the installer and when it asks where to install, give it C:\PMAIL. It recognises an existing installation and upgrades the program files while leaving the MAIL folder alone. This is the step that turns a 3.x or early 4.x install from XP into a current one. Untick any offer to create a new mailbox, since the copied one is already there.
Start Pegasus, check the folders and the accounts
Open Pegasus from the new shortcut. Every folder should be listed with its messages. Under Help > About > Info confirm the home mailbox path is inside C:\PMAIL\MAIL. Then open Tools > Internet Options and check the mail accounts. POP and IMAP settings carry over. Gmail accounts need to sign in again, because 4.91 replaces the old password login with Google's OAuth2 sign-in, which is one of the reasons to upgrade rather than run the XP copy.
Why Will the Old PC Not Show Up on the Network?
Because the two machines no longer share a language. Windows XP offers file sharing over SMB version 1 and nothing newer. Windows 10 and Windows 11 stopped installing the SMB1 client by default some years ago, after it was used by the WannaCry and NotPetya attacks, so a Windows 11 PC opens its Network view and the XP box is not there. Windows 7 can speak SMB2, so sharing from a 7 machine usually works, but it is still slower than a USB copy of a folder that is rarely more than a few gigabytes.
You can turn SMB1 on in Windows 11 through Turn Windows features on or off, under SMB 1.0/CIFS File Sharing Support, and turn it off again afterwards. For a one-time copy it is rarely worth it. A USB stick, an external drive or the old hard drive in a USB adapter gets the folder across with nothing to undo later.
Half the Pegasus mailboxes we see come off a drive that was pulled from a dead XP machine. The folder is nearly always fine. PMM files do not care what version of Windows wrote them, which is the quiet advantage of a program that kept its file format for thirty years.
What If You Are Leaving Pegasus on the New PC?
Then stop after the copy. The MAIL folder inside the copied C:\PMAIL is all that a converter needs, and Windows 11 never needs Pegasus installed for that. Univik Pegasus Converter opens the user folder, shows the tree with its real folder names and writes an Outlook PST, a Thunderbird profile, MBOX, EML or a set of PDFs, with attachments and dates kept. The old machine can go to recycling the same day.
The one thing to export from inside Pegasus before you switch it off, if it still runs, is the address book. Open it, choose the export option and save a CSV or text file, because address books are not mail and a mail converter leaves them alone. The guides to Pegasus Mail to Outlook PST and Pegasus Mail to Thunderbird pick up from here.
Upgrade in Place, Convert or Share Over the LAN?
Three ways to get the mail from the old Windows to the new one. The first keeps Pegasus, the second replaces it, the third is what most people try first and regret.
| Question | Copy and install 4.91 | Copy and convert | Network share from XP |
|---|---|---|---|
| What you do | Copy PMAIL, install 4.91 over it | Copy PMAIL, convert the MAIL folder | Enable SMB1, share over the LAN |
| Old PC must boot | No, the drive alone is enough | No, the drive alone is enough | Yes |
| Keeps Pegasus | Yes, upgraded to 4.91 | No, mail moves to Outlook, Thunderbird or others | Yes, same version |
| Filters and address books | Come along | Address books are exported separately | Come along |
| Gmail works afterwards | Yes, with OAuth2 sign-in | Yes, in the new client | Not on 3.x or early 4.x |
| Cost | Free | Trial, then paid | Free |
| Time | About 30 minutes | About 20 minutes | An hour or more |
Univik Pegasus Converter reads the copied MAIL folder on Windows 11 with no Pegasus installed and writes Outlook PST, Thunderbird, MBOX, EML or PDF with every folder in place. Good for a mailbox from a 16-bit Pegasus too, since only the files matter.
Windows 11 and 10 · offline · the trial handles a sample of messages per folder so the output can be checked first
The short version
- Pegasus Mail 4.91 (August 2025) supports Windows 7 to 11. Only the 16-bit 3.x edition cannot run, and its mailbox still can be read.
- Copy all of C:\PMAIL by USB or by pulling the drive. XP is invisible to Windows 11 over the network because of SMB1.
- Put it back at C:\PMAIL, never in Program Files, then install 4.91 into that folder so it upgrades in place.
- Check Help, About, Info for the mailbox path and sign Gmail in again with OAuth2.
- Not keeping Pegasus? The copied MAIL folder converts to PST, Thunderbird, MBOX, EML or PDF without installing it.
Convert the old Pegasus mailbox instead, free trial
Windows 11 Questions
About This GuideThis guide is by Leena Taylor Paul of Univik, which has made Windows email software since 2013. The 4.91 version, its August 2025 date and the Windows 7 to 11 support line were read from pmail.com in September 2026. The SMB1 behaviour matches Microsoft's documentation for Windows 10 and 11, and the Program Files redirection is the fault behind most of the Pegasus start-up reports Univik support receives. 22 September 2026. Stuck partway through the move? Tell support which step and what Pegasus shows.
Sources: pmail.com: Pegasus Mail version information · pmail.com: v4.9x release notes · Microsoft Learn: SMBv1 is not installed by default · Univik Pegasus Converter