Receiving multiple copies of same e-mail after upgrade

Please try these steps below:

Try to uninstall incredimail and install it again and see if that fix the problem
if not then try remove your email account from incredimail and add it again
you have to make sure there is no email in the outbox
if  problem still persist then try to check your incredimail if  by mistake you have two same accounts added
if yes then remove one  account and check the problem is fixed or not

if problem still persists then please contact us incredimail@gmail.com