TS3276 Beginning on December 23rd I was no longer able to receive incoming emails on my computer. They appear on the server. My iphone can retrieve them, but my mail program on my computer can't see them. I tried deleting and recreating account. Didn'

Question

I'd been using the program on the same computer for years.  I've tried just about everything now, backing up my email boxes to my desktop and deleting them, creating a new account and deleting the old one.  I've checked the behaviors.  I've dumped tons of old emails.  Help.  There is one other thing that was happening in the months before that I didn't realize.  As my computer downloaded the incoming files, they were not being erased from the server.  I don't know why.  I hadn't changed any settings.  The Rep from my server company insisted it was that I'd maxed out the program or something was corrupt and recreating the account would help.  It didn't.  When I'd done everything else and backed up everything, I also tried deleting the Cache in the Finder.  No difference.  Help.

Answer 1

How much mail are we talking about here?  Roughly how many messages, and roughly how many gigabytes of mail?
Who is the mail provider?  Is this a local provider on a local network, or one of the "free" providers, or something from your ISP?
Do you have free disk space on your OS X system here, or is it possible that your disk is getting full?
As for the usual diagnostics for problems with Mail.app, launch Mail.app and select the Connection Doctor from the Window menu, let it run, select More Details, and re-run the tests.  Expunge any personally-identifying information and post the results here, if they don't make the trigger clear.
You can also try a mailbox repair pass; there's a Rebuild option in the Mail.app menus.
If the downloads are failing, then the usual trigger is the IMAP or POP password setup; there are two entirely seperate connections and two separate credentials and such; the send path (SMTP) and the receive (IMAP or POP) path.  Usual triggers for problems are changes to the mail servers involved, or the mail ports, or the credentials needed; I've seen vendors change each of those, and forget to mention it to their users.
That OS X version is extremely old.  (I don't have anything nearly that old to check the details fo the setup of that version; 10.6.8 is the oldest OS X version I have handy.)