I see your post where you included what you thought was the headers has shown up in this thread.  That content is the entire message.  If you were to replace the content of the Subject header (everything from and including the beginning '=' sign and through the ending '=' sign) with something like Bad CNM then place it in your mailbox folder (c:\pmail\mail) you would then be able to see the message in the Pegasus Mail new message folder.  It's really not worth the effort since it is a worthless message but if you find this intriquing, go for it.

When I try to start Pegasus, it refuses and offers the error message Visual C++  "The program has requested the runtime to terminate in an unusual way"

This all began after a long batch process using Adobe Camera Raw that lasted overnight. The batching went well, but since then, Pmail isn't opening.

What can I do to fix this?

Same problem here except crash occurs when I try to access an attached mailbox.  Since the attached mailbox is 'user' to which I divert all Spam and delete all messages periodically throughout each day I suspected the problem is being caused by something in a message that came in last night.  I moved all .cnm file out of the Spam mailbox then tested.  No crash.  So, it appears to be a new message that is causing the problem.  To find which one, move all .cnm files out of your mailbox folder that have date/time stamps later than the last time you used Pegasus.  Start Pegasus and see it if starts up.  If it does, move a few .cnm files at a time back into the mailbox folder until the crash occurs then narrow it done the specific file causing the crash.  Keep track of the ones you move back because once the crash occurs you will need to know which ones you had just moved in order move them back out then in again one at a time to find the culprit.

I haven't started on mine yet so will post back if I discover anything additional worth sharing.

Brian:

Mine won't start up at all. I deleted the entire folder and replaced it with a fresh copy from another computer and this new version works fine. This leads me to believe that there's something in the box that's doing this too.

However, I don't know how to get to the messages without opening the version that's storing them so I can't delete or transfer specific ones to test this. I have the dysfunctional installation on a USB stick now and could dissect it if possible.

I really would like to see the emails I missed.

You need to use Windows Explorer and navigate to the mailbox directory (C:\PMAIL\MAIL\ADMIN in a default install).  If you are not working in Pegasus as the default 'ADMIN' user then select the mailbox directory that corresponds to your Pegasus user.  It is in there where you will find the .cnm files and can start identifying which one is causing the problem.

I found mine!  Anyone want a copy to do some analysis on?

I have no MAIL\ADMIN  folder. When I open \MAIL\, there's just a whole bunch of files.

Earlier you said "I deleted the entire folder and replaced it with a fresh copy from another computer and this new version works fine."  Did you replace the entire C:\PMAIL folder with the copy from the other computer?

In the one that is working now, go to Help > About Pegasus Mail then click the Info button.  Look at the entries for the home and new mailbox locations and report those paths back to us.

Brian:

 To be more specific, I removed the entire C:\Pmail folder from the hard drive and put it on a USB stick. I think took a different entire C:\Pmail folder and copied it to this machine.

Here it is.

 *******

 Pegasus Mail for Microsoft Windows
Copyright (C) 1992-2011, David Harris, all rights reserved
Electronic mail to support@pmail.gen.nz.

WinPMail version: Version 4.63 (Win32), Dec 22 2011, build ID 325
Language resources: Standard UK English resource set
Extension Manager version: 1.14
Operating mode: Standalone
User name and ID: Single-user mode, 0
Windows version: 5.1
Windows flag word: 0
WINPMAIL.EXE directory: C:\PMAIL
Home mailbox location: C:\PMAIL\MAIL
New mailbox location: C:\PMAIL\MAIL
TMP environment variable: J:\DOCUME~1\Owner\LOCALS~1\Temp
TEMP environment variable: J:\DOCUME~1\Owner\LOCALS~1\Temp
LAN-based SMTP support: N, N, N
NetWare MHS support: N, N, N
Built-in TCP/IP support: Enabled
  - WINSOCK version: WinSock 2.0
  - WINSOCK path: J:\WINDOWS\system32\WSOCK32.DLL
Commandline:
Active -Z options: 32768
PMR variable: (None)
PML variable: (None)
MAI variable: (None)
NB variable: (None)
Autofiltering folders: 0 (0 active, 0 inactive)
Last new mail count: 4
Message size soft limit: 0 bytes
Message size hard limit: 0 bytes
Attachment size soft limit: 0 bytes
Attachment size hard limit: 0 bytes

And Brian...

Thank you for your concern! It is truly appreciated.

[quote user="Byarvin"] To be more specific, I removed the entire C:\Pmail folder from the hard drive and put it on a USB stick. I think took a different entire C:\Pmail folder and copied it to this machine.[/quote]

That's cool.  Rename the current C:\PMAIL folder to C:\PMAIL_OLD then copy the entire C:\PMAIL folder from the USB drive back to C:\PMAIL.  Now open C:\PMAIL\MAIL and move all recent .cnm files to a temporary location like C:\TEMP\CNM_FILES.  Start Pegasus.  If all is well, start moving the .cnm files back to C:\PMAIL\MAIL as previously described. If you don't have many you can move them one at a time while Pegasus Mail is running.  Check the new mail folder after each one is moved to make sure it is visible before moving the next one.  Pegasus Mail will crash as soon as soon as it attempts to record the problem message into the new message list.

Worked perfectly! Amazing. It had nothing to do with C++ at all. I can't thank you enough.

Did you look at the problem .cnm file with a text editor?  Did you save it?  I am curious whether we can identify any similarity between mine and yours.  Mine was a message generated by SpamAssasin with the original message content attached.  I received around 50 SpamAssasin generated messages this morning but only the one caused a crash.

Brian:

It only showed a header in notepad and wouldn't open in a word processor at all.

 Here's the header:

 Return-path: <joyzyjchodpevby@aol.com>
Envelope-to: brian@brianyarvin.com
Delivery-date: Wed, 06 Mar 2013 00:05:31 -0600
Received: from oms-mc01.r1000.mx.aol.com ([64.12.81.66]:51080)
    by gator1316.hostgator.com with esmtp (Exim 4.80)
    (envelope-from <joyzyjchodpevby@aol.com>)
    id 1UD7Tm-0002f6-ND
    for brian@brianyarvin.com; Wed, 06 Mar 2013 00:05:31 -0600
Received: from mtaomg-db03.r1000.mx.aol.com (mtaomg-db03.r1000.mx.aol.com [172.29.51.201])
    by oms-mc01.r1000.mx.aol.com (AOL Outbound OMS Interface) with ESMTP id C19E138001BAC;
    Wed,  6 Mar 2013 01:05:29 -0500 (EST)
Received: from core-mha002c.r1000.mail.aol.com (core-mha002.r1000.mail.aol.com [172.29.238.130])
    by mtaomg-db03.r1000.mx.aol.com (OMAG/Core Interface) with ESMTP id 59705E000082;
    Wed,  6 Mar 2013 01:05:29 -0500 (EST)
To: ttaylor@aamu.edu
Subject: =?ascii?B?RlJFRSAgVHJhbnNVbmk=?==?utf-32?B?b24sIEVxdWlmYXggICBhbmQgRXhwZXJpYW4gICBTY29yZXMgIERlbGl2ZXJlZCA=?==?utf-16?B?IAAgAEkAbgBzAHQAYQBuAHQAbAB5ACEA?=
X-MB-Message-Source: WebUI
MIME-Version: 1.0
From: joyzyjchodpevby@aol.com
X-MB-Message-Type: User
Content-Type: multipart/alternative;
 boundary="--------MB_8CFE847BCA57A36_1600_24856_webmail-d252.sysops.aol.com"
X-Mailer: AOL Webmail 37488-STANDARD
Received: from 178.94.52.153 by webmail-d252.sysops.aol.com (205.188.17.49) with HTTP (WebMailUI); Wed, 06 Mar 2013 01:05:28 -0500
Message-Id: <8CFE847BCA318D5-1600-AD23@webmail-d252.sysops.aol.com>
X-Originating-IP: [178.94.52.153]
Date: Wed, 6 Mar 2013 01:05:29 -0500 (EST)
x-aol-global-disposition: S
X-SPAM-FLAG: YES
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com;
    s=20121107; t=1362549929;
    bh=Dv3EsacfiRtyE+wizWqfNSVUZbPgZKDfd7ZjA27k8XA=;
    h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type;
    b=WYsRS9q8Y8ltrj6Ho2IJMceU4CqaWfWVUS+D6Ta+L1l9ij3v95D6d7uv5ILBrP/sB
     rORn3sHnzWKgKX28u9fKuSzoEDyXLZiEphBxLWftD/bZodj5fefw1b9VoVlVs0Mx/R
     cPhAFDa7KoFkPk2HSOWtXSh/tJf0s4QJ8Y9IA3a0=
X-AOL-SCOLL-SCORE: 1:5:14516359:93952408  
X-AOL-SCOLL-URL_COUNT: 4  
X-AOL-REROUTE: YES
x-aol-sid: 3039ac1d33c95136dca95b7b
X-Spam-Status: No, score=2.1
X-Spam-Score: 21
X-Spam-Bar: ++
X-Spam-Flag: NO
X-PM-PLACEHOLDER:                                          .

This is a multi-part message in MIME format.
----------MB_8CFE847BCA57A36_1600_24856_webmail-d252.sysops.aol.com
Content-Transfer-Encoding: quoted-printable
Content-Type: text/plain; charset="us-ascii"

http://j.mp/YTzkyI

http://j.mp/VAeYg5
----------MB_8CFE847BCA57A36_1600_24856_webmail-d252.sysops.aol.com
Content-Transfer-Encoding: quoted-printable
Content-Type: text/html; charset="us-ascii"

<a href=3D"http://j.mp/YTzkyI"><img src=3D"http://j.mp/Ytkxf2"></a><br><br>
<a href=3D"http://j.mp/VAeYg5"><img src=3D"http://j.mp/W42VXp"></a>

----------MB_8CFE847BCA57A36_1600_24856_webmail-d252.sysops.aol.com--

The content of the Subject header is the problem!  Removing the Subject header content from the original .cnm file eliminates the C++ crash.

Here's the content of the Subject header:

Subject:  =?utf-16?B?RgBSAEUARQAgACAAVAByAGEAbgBzAFUAbgBpAG8AbgAsACAAIABFAHEAdQBpAGYA?==?ascii?B?YXggIGFuZCAgIEV4cGVyaWFuICAgIFNjb3JlcyAgICBEZWxpdmVyZWQgICBJbnN0YQ==?==?utf-32?B?bnRseSE=?=

Wierd line breaks when pasted here but this is all one line in the original .cnm.

Man! You are amazing! Is there any content in the message worth looking at?

Nope, it's junk mail. 

FYI, .cnm files are plain text files so you can look at the contents with a text editor like Notepad or Wordpad.

Brian:

It figures! Could you imagine how I'd feel if it were important correspondence from a client or relative?

You have been great here!

Once again, thank you for everything.