WinPMail version: Version v4.91.1746, 11 Aug 2025 18:19:07, build ID 1746

We recently updated our Pegasus installation from 4.81 to 4.91, and since then have encountered an issue. Where an email is forwarded to users in the same domain, it gets rejected by our mailserver service (Rackspace). The error message is:
user@company.com: host mx1.emailsrvr.com[xxx.xxx.xxx.xxx] said: 550 5.7.0
mime_banned_file - Your message has been rejected because it contains a
banned file attachment (G1B) (in reply to end of DATA command)

The original email was a few lines of text (a support query from a web-form), nothing fancy. Checking the email in the rejection message, it seems to have acquired an additional *.TMP file.

Forwarding the same email to other domains (gmail, Yahoo) seems to work normally, but again with the additional *.TMP file.

The setting in Tools->Options->Outgoing->Use MIME Features is set to On. When the setting Use MIME Features is set to OFF, these emails are sent as usual, but this causes other issues that make this fiddly/impractical.

Any thoughts/suggestions on resolving this?

I am clueless. I have four email accounts with differing hosts (gmx, rr, zoho, and gmail); only gmail allows bouncing. I bounced several messages to some of the other accounts. No .TMP was included in any of them.

I am curious what the content of the .TMP is though.

I'm also surprised by the rejection of a .tmp file attachment by Rackspace unless the rejection is on something detected within the .tmp file.

Here's an example of TMP file content, amended for anonimity:

CLIENT DETAILS=0D=0A=0D=0AName: Andy=0D=0AOrganisation: COMPANYNAME=
=0D=0AEmail: user@COMPANYNAME.co.uk=0D=0ATelephone: =0D=0A=0D=0AP=
RODUCT DETAILS=0D=0A=0D=0AProduct: PRODUCTNAME=0D=0AVersion: =0D=0A=
=0D=0ADETAILS=0D=0A=0D=0ASubject: Email Test=0D=0AMessage=0D=0A=0D=0A=
Created to test email rejections.

An additional point, the rejected mails were edited and forwarded, not bounced. I just tried bouncing one, and that works fine.

Pegasus Mail creates a lot of .TMP file containing the content of the message being sent. I guess that is temporary file used during creation of the final form, or perhaps is the final form. It makes me wonder whether this .TMP file is getting attached somehow, although Pegasus Mail creates a lot of .TMP files so it may not be the actual message file. I remain clueless.

HTH,

The *.TMP attachment is not part of the original email. It only appears when the email is forwarded, and the Edit option is chosen. If the option to remove attachments is chosen, or another forwarding method used, the email is delivered without problem.

I've looked at some similar older emails forwarded in the same manner using an older version of Pegasus. They had an attachment (created by Pegasus?) with suffix *.PM$, which was delivered successfully.

Thanks for the help working out the cause of the issue, and how to get around it.

I have to backtrack on my last assumption. It appears that Pmail is automatically attaching a temporary file containing the contents of the message being edited when it's being forwarded. I've been able to confirm this. This issue is also being discussed on the PM-WIN list.
I won't downgrade Pmail 4.91 as this minor nuisance affects me little. I notice that as soon I hit the Forward button the Attachments tab shows (at least) one attachment. Temp files appear to have NO file name and location and can be easily removed before sending.
My suggestion was that this issue be brought to David H.'s attention ASAP.

I have sent

Done.

For now, the only workaround I can think of is that before you hit the Send button on a forward with edit, you check the Attachment tab and remove any superfluous attachments.

The .TMP attachment will appear like this in the Attachments tab when forwarding a plain text message with editing and including attachments:

One thing I was thinking might work.
Click on the send for the forward message, but don't have it do the SMTP connection.
Then with Pegasus still open, open the PMX file with a text editor, and just change the extension of the base64 code from .TMP to .TXT or something else. Then the server wouldn't see the .TMP banned extension.

Seem to have found the cause of the issue.

If that is checked it creates a PMX file as stated below.
If it is unchecked, it creates a PMW and PNX files that do not contain the .TMP attachment.
Not sure why if original message has no attachments, if this is check, it creates the attachment.
Also, tested 4.81pb3 and it has this defaulted to unchecked, but the 4.91 seems to have it checked as default.

So, seems unchecking the option should solve problem. Don't know if default was changed for a reason, or just remembers last setup. Could be that a check to turn this off, if original message has no attachments?

The messages I sent to support.

Did further testing. and discovered this?
Did forward with Edit and the default add attachments is check,
even thou message didn't have any attachments. It creates and PMX
file that does have the base64 encoded contents of message with
.TMP extention.

9700 Oct 2 19:42 6CYID0MI.PMX

--Message-Boundary-24654
Content-type: Application/Octet-stream; name="QYGKVTGX.TMP";
type=Plain text
Content-description: Mail message body
Content-disposition: attachment; filename="QYGKVTGX.TMP"
Content-transfer-encoding: BASE64

If I unchecked the Box, it created these two files.

341 Oct 2 19:52 VDYAR9K3.PMW (File with header options)
5901 Oct 2 19:52 VDYAR9K3.PNX (RTF version of message)

So, it would appear unchecking that will solve option, or perhaps
one could manually remove the attachment before sending.

Don't know why it would use different methods for message.

Only issue would be if forwarded message did have attachments
that are wanted to be forwarded.

Don't know if this was an option added in 4.91 (If someone has 4.81
arround could check), or perhaps it was uncheck or just unnoticed
before?

As added info. The setting is in PMAIL.INI
Integer preference block 1 = 12319 24000 0 0 0 0 0 7 0 1 0 0 0 0 0 0
Integer preference block 1 = 12319 24000 0 0 0 0 0 7 0 0 0 0 0 0 0 0

One line has 1 other shows 0?
Would think 0 is unchecked and 1 if checked?

The Integer preference block entry exists for each identity.

Yes, it is in the PMAIL.INI in each mailbox.

Was just showing what changed in the PMAIL.INI file when one turns on/off the option to attach the attachments.

Again, not sure why if the email has no attachment in original email, that Pegasus creates an attachment with the .TMP extension.