Phantom Blank Spam blocking Mail from retrieving new mail in Apple Mail

Question

Over the past few days my wife and I have both had difficulties downloading pop-3 mail from our accounts (from a UK based ISP, UKonline) onto our separate computers (Powerbook G4 and MacBook). I have no idea yet whether this is affecting other ISPs or other Mac or PC platforms or mail clients, but it is definitely affecting both of our Mail apps running under 10.4.7.
The problem seems to revolve around blank email messages being received into our respective accounts by at our ISPs mail server.
These blank messages, presumably some form of spam have no sender, no recipient, no date, no source code, no body text and no subject.
These 'phantom' blank emails appear to be the root of the problem as once they are manually removed from our server-side inbox (either through Apple Mail's 'Get Info' / 'Remove from Server' function, or via our ISPs webmail facility), the email starts picking up mail automatically again–immediately, without any other intervention other than clicking 'Get Mail'. Until they are removed, Apple Mail will NOT collect any more mail, automatically or manually through 'Get Mail'.
I have contacted my ISP and to date had no firm response from them. One of their operatives suggest I contact Apple as his Windows PC email still works and retrieves mail when these blank phantom messages reach his server-side inbox waiting to be collected.
The fact that these messages have no date means that under Mail's 'Get Info' / 'Remove from Server' facility, they always appear at the top with the CURRENT date and time when sorted by date. In this way, they are easy to spot. Also, if sorted by size, they also appear at the top because they are 0k in size. They appear to act as a blockage to receiving new mail until they are cleared.
I'd be grateful to hear if anyone else is having this problem or has found a solution to it, or indeed whether this is an ISP problem.
With thanks
Jamie
Powerbook G4 17" 1.67GHz & MacBook 1.83   Mac OS X (10.4.7)   Macuser since 1987; Apple IIe veteran.

Answer 1

Hello Jamie.
These 'phantom' blank emails appear to be the root of the problem
as once they are manually removed from our server-side inbox
(either through Apple Mail's 'Get Info' / 'Remove from Server' function,
or via our ISPs webmail facility), the email starts picking up mail
automatically again–immediately, without any other intervention
other than clicking 'Get Mail'. Until they are removed, Apple Mail
will NOT collect any more mail, automatically or manually through
'Get Mail'.
What is your setting for removing messages from the server when downloaded by the Mail.app?
If set to right away, does this have any effect?
One of their operatives suggest I contact Apple as his Windows
PC email still works and retrieves mail when these blank
phantom messages reach his server-side inbox waiting to be collected.
Of course - especially if this operative is using Microsoft's Outlook or OE which usually don't have problems downloading anything including viruses, adware and spyware.
I'm not sure why these "Ghost" spam messages cause this problem with the Mail.app but these are obviously sent by a spammer to cause problems.
How about your ISP doing something about blocking all messages at the incoming mail server that are completely blank such as these so they don't arrive in any of their customer's Inbox mailbox at the server since these messages are intended to cause problems and are completely blank anyway? No different from any other type of spam or as messages are scanned for viruses at the server. Although Apple needs to look into this, your ISP is not completely off the hook or has no responsibility IMO.