User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:56.0) Gecko/20100101 Firefox/56.0 Build ID: 20171024165158 Steps to reproduce: On 52.4 Deleted popstat.dat to start clean and also took note of other earlier problems. Downloaded 531 emails from server. Did get again .. no emails downloaded Did get again later .. 531 emails downloaded again. Each time I start tbird now get same problem Actual results: Multiple copies of downloaded emails Expected results: Should just get one copy of email downloaded and then not get duplicates on next get.

> Did get again later .. 531 emails downloaded again. This is always after a startup?

It can be running for a while and not just after startup. I am wondering though if it is a problem with the yahoo pop server? I switched to the "plus" version of their pop server (plus.pop.mail.yahoo.com) and so far not had a recurrence of the problem. I also went back to being on the Thunderbird beta program and installed version 57b1 but still had same problem until I switched pop servers.

Perhaps Tony can help

You can close this one. It was a yahoo server problem that once I switched to plus.yahoo ... I did not get a recurrence. Thx for investigating. Gordon