In our case, I have narrowed it down to SPAM with illegal characters. There is one particular type of SPAM that puts every conceivable key combination and unicode structure in the title to get your attention. It also causes mail servers to choke.
If the downloading fails to proceed a second time, I must use a web client to delete the offending message. RH Hiro wrote: >Interestingly, in my case, it has been 100% Spam mails that hangs, but >the source code of the mail itself doesn't show any suspicious code nor >attachment.
