Files with .pro ext in Mailin directory

[FTesterman]

While debugging a different issue, I noticed that you referred several people to examine / capture messages in the Mailin folder. I figured out our problem was from a totally different source, messages sent in HTML rather than plain text.

While looking at the Mail folder though, I noted approximately 400+ files with the naming structure: recipientname$12345678901234567.pro or ftesterman$73244044304224733.pro. The majority of these have older dates; 2006 for example.

What are these files? Do they need to be purged at some interval?

[Tech Support]

The .pro files in the MailOut folder are files that are currently being delivered in an outbound SMTP session. The .rtr files are ones
that failed delivery and will be tried again later.

If you see .pro files that are not in the MailOut folder, they can be deleted as they are temp files that weren't properly moved to the MailOut folder for processing.