Using Windows 10 and TBird 102.5.1 and POP3, HostGator hosts my mail on their server. I have seven e-mail accounts in TBird, all on the same domain that I own. Mail is hosted by HostGator. My most-used account redownloads the same messages repeatedly. The account checks for mail every minute but the repeats happen only 5- to 8 times a day. This is happening on only this one account and no other. Things I've tried and additional facts: * deleted popstate.dat so it would rebuild on next use of TB several times over the last two weeks * deleted inbox.msf so it would rebuild on next use of TB several times over the last two weeks * uninstalled TB, deleted all TB related files and folders on the computer, restarted the computer, then reinstalled TB from scratch. I transplanted NO files from the old installation, three times over the last two weeks * deleted popstate.dat again, and inbox.msf. * verified that I am deleting the proper popstate.dat and inbox.msf files for the troubled account. * Mails on phone are normal, no duplications. * I've run HD and memory tests several times, all negative. * Repeats do not happen on every download; it is sporadic several times a day In weeks prior to this problem I had multiple TBird problems, mostly mail sporadically not being delivered or being delivered anywhere from a few hours to as much as four days late and some not at all, much less than half was delivered timely. I worked on that off-n-on for two weeks and it appears the delivery problem went away on its own as nothing I tried produced a change. As soon as the delivery problem went away, this repeating problem appeared.