About 20 times a day, I get an error from mail.app saying that my password was rejected by the mail server (POP server, offsite). I only get this on my main machine, never on my secondary laptop. My wife and several others use the same mail server and domain with no errors. I know there is supposed to be a problem with corrupted keychains causing this, but I have tried all the fixes I have heard of -- running keychain repair (no problems found), replacing the keychain with one from another machine, deleting the keychain and creating a new one -- nothing seems to change this behavior at all. I even had this happening when I was on a different mail server, so all of the evidence seems to point to it being something with this one machine. Mac OS X 10.4.5 (problem started with 10.4.3), G5 dual 2 GHz PowerMac, 2 GB RAM, 6MBPS/1.5MBPS internet connection.