Version: 1.10.1 (using 4.1.2 (KDE 4.1.2), Kubuntu packages) Compiler: cc OS: Linux (i686) release 2.6.27-4-generic In reality I don't know if kmail is long or not. I kill it after something like 30 minutes and 50% usage of memory and most of all nothing or more scarry the number of message in my imap account (gmail) decreasing. In reality it seems that kmail didn't delete anything but just in case I close the application. So to be clear: I configure my imap account, I click on the inbox icon for this account and I wait and wait that my messages appeared in the window. I tried with thunderbird and I don't have any problem so the problem is kmail related.
Your mailbox is probably quite big, isn't it? If it is, this is probably a duplicate of #125084 *** This bug has been marked as a duplicate of bug 125084 ***