TCPView from sysinternals shows that Yahoo! email opens up a huge number of "endpoints". Maximum observed number so far is 292. 200 is not uncommon. Most are classified as "Close Wait:".
No apparent harm being done, just slow.
Sometimes the send button or the delete button opens a little box that says "Loading", then the box closes, and nothing else happens. Nothing deleted, mail not sent.
If you click "Send" twice the mail gets sent twice, sometimes.
Sometimes clicking on one of the radio buttons just doesn't do anything.
Sometimes it is necessary to go back to "Check Mail" and start again.
ESET online, Avast! and MBAM say this system is clean.
Anyone know whats up with that? Other email services don't do it.
To be fair, I contacted the email help about a different issue and they were prompt and helpful.