Thousands of non existant emails being downloaded by windows live email client

Windows live mail on two of our computers are acting crazy. they are downloading thousands of messages/emails which are non-existant every now and then. the downloading just goes on and on and never stops until we find it out and manual stops it. During this time we do not receive any real emails that have been received at the webmail server. it is webmail of a company that has been configured in the windows live mail client and we always delete the past emails from the email/webmail server. Still this phenomenon occurs and this is realy annoying. please help me to find a solution to this problem

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