[plug] email left on ISP's server

[Gavin Chester]

I have developed the practice of setting my mail client to leave a copy
of my hosted-business-address emails on the host server for two reasons:
1/ to have a remote archive; and, 2/ to allow for accessing mail from
different PCs that aren't otherwise kept in sync.

Trouble is, with the archive building up to several thousand messages it
slows down the checking for new mails.  Bigger trouble is, every now and
then something goes haywire and all the flags saying that I have already
retrieved any particular mail to a particular PC seem to be reset and I
have to endure the download of all several thousand messages as
duplicates in my inbox.  A real pain on dialup :-(  

What I want to know is this:
Is this a problem with my ISP resetting the mail server somehow and
losing sense of the fact that I have already downloaded those emails? It
happens with the frequency of a few times a month, but it doesn't happen
under any consistent conditions my end, which is why I suspect my ISP
stuffing things up.  I have always suspected that my email client was at
fault (evolution), but there is no pattern to when the repeat download
is likely to happen.  Plus it only happens with addresses hosted by that
provider.  Would you say I have grounds for complaint with them and that
nothing could point to trouble my end?

Gavin