I cannot access my Apple email

[nellie]

desktop iMac 10.2.8

I cannot access my Apple email. I have to retrieve and send email through Comcast. When I click on the Apple postage stamp icon, I get a message that says (this is the short version): "The mailbox on.." (and then it says my name and my host number on Comcast) "is currently locked on Comcast.net. If you open a mailbox that is already in use, you may damage its contents." Then there are three choices: open read only, quit, open anyway. When I click on any of these, nothing happens. Comcast says this is an Apple problem. I can only get out of this email screen by doing opt, Apple, esc. I literally have about 2,500 emails in the inbox because this has been going on for some years now. Of course, I have accessed my emails through Comcast. I went to the Genius Bar at the Mall of America, and they suggested I do search/run disk utility and then repair disk. That did not work. I have tried the HELP section a zillion times, but cannot figure anything out. Any ideas?

 

[Egidio]

That large number of messages in your inbox could be a reason for the problem. It's best to move any messages you have to other folders and leave your inbox free for new mail. Once new mail is received, it should again be moved to other folders.

What type of email are you using? POP or IMAP?

 

[nellie]

POP. I cannot move my messages to other folders. Mail will not let me do ANYTHING! I now have 3,387 messages in my inbox; 12 in draft; 11,452 in trash (honestly!) It will not let me delete the ones in trash either. Whenever a new message comes into the inbox, the system lists it four times for the same message. I think the problem goes back to my original quote above: "That my mailbox is currently locked on Comcast.net" (but Comcast says it is an Apple problem.)