I have 2 POP accounts and 2 IMAP accounts in Mail.....

Take a screenshot of the settings you are using (obscure the email address) and post it here.

You have no POP accounts, why do you think that you have 2?

Your accounts (as displayed here) are all Imap and are all set to store mail on the server and on your local machine.

Mail must be being moved by rules, check your rules, if necessary disable them for now. Also check that your mail (at the providers website) matches the mail in Mail.app on your local machine.

altv wrote:

Csound1

I said earlier that I have changed all my 2 POP addresses and created imap addresses for them. It seems to receive and send OK but will not retain them in my inbox and certainly does not retain them in my inbox on my webmail system.

All the e mails from the notification system on this support forum have all vanished.

Since you say they are supposed to be on the server and on my machine, why are they not showing? I am literally no further forward now than I was when I started this discussion.

Clearly your installation is borked, not running correctly.

Reinstall OSX.

Also .... Who is your email provider, I wish to check whether they actually support Imap access.

😐

It supports Imap, but do you realise it sends in the clear? no security.

Backup and remove all the accounts, add them back one at a time following the Plusnet instructions exactly.

I would change to a secure system Plusnet is not.

Uncheck "Use Idle if Server Supports It" (on an insecure system I would pull rather than push)

Now that you have awarded your self the solution greenie you may get less people checking it (because you marked it solved) if required you should start a new post.

altv wrote:

Csound1

I am loathe to reinstall Mountain Lion again. It has been put in twice since it came out and both times by Apple engineers over the phone because of the complete lack of stability in this machine. (Garbage is the word that comes to mind!) This meant deleting the old Lion system and starting from scratch. And of course, I have to download it again, because Apple, in their wisdom, will not allow you to keep it even though I bought it from the App Store. The machine is only 9 months old, and doesn't really get used in anger, because I am now retired and only really use it for Home accounts, letters and the odd spread sheets and when I can, e mails!!

Cheers

altv

I have none of your problems, a reinstall is exactly what I would do, but it's your machine. Good Luck.

PS: Apple allow you to keep the installer as long as you like, you have to remember to make a copy however, next time, do that.

You can reinstall ML 'in place' (that is the default) nothing else should be affected .. but this is the real world so I advise backing up first.

If this does not cure the problem then I suspect that the issue lies outside your machine.

Do this (it's a test) make a rule in Mail to copy all incoming Mail to a local inbox as it arrives, then see if the email vanishes from it as well as the server folder.

Also are you losing email from all accounts or only some?