Error returned on second 'send/receive' mail



I use gmail and Windows Mail frontend. When I start Windows Mail and click
Send/Receive all works ok and I either get new mail or none. If I click
Send/Receive again I get "Some errors occurred . . . " but there is nothing
in the box below. At least I can get my mail but have to kill & restart to
get a second time. I'm stumped.
.