Duplicate email messages

I've had only one duplicate in the last few hours and a constructive suggestion concerning my email client so unlikely to be AVG.

Sorry to have troubled you.

Hello Keith,

I will check this for you.

We have never heard of such a behavior with AVG.

Please disable AVG AntiVirus free temporarily on your computer and check if everything works fine.

Yesterday I changed antivirus from Bitdefender to AVG Free and today am now finding duplicate messages in my mailboxes.  Not all are duplicated, only about half of them.

To try to whittle down the possibilities, first I closed my email client, Eudora, waited a couple of hours and then logged-on to my ISP's webmail where I found nine emails, none duplicated so the ISP is less likely culprit.

I then restarted Eudora and these same nine messages became 14 when they were received by Eudora.

Because of the timing (i.e. just changed to AVG Free) I'm wondering if  it could be the combination of AVG and Eudora. I'm asking here if anyone has previously experienced this and if so how it was reduced or eliminated.

I disabled AVG antivirus and in the four hours since then have only received five emails. 

However, none of them was duplicated. 

I will continue for a while longer.

Dear keith,

Thank you for keeping us posted. Please reset the email configuration Eudora and monitor the status. Further, you can contact Eudora to check if there is any issue with the email client. Thank you.

Hello Keith,

I will check this for you.

We have never heard of such a behavior with AVG.

Please disable AVG AntiVirus free temporarily on your computer and check if everything works fine.