"The good thing about not having a specific forum is that when an Opera Mail thread is posted in a the Windows or Mac or Linux forum, I know what OS they're using. "

I subscribe to a car forum where in order to post, you have to select a catagory such as engine, electrical, etc. Could do the same with Windows, Linux, Mac, etc ... if the forum software provides such capability.

Also, I don't know how long ago MS-AV found the file. It could have been on that run or years ago. It doesn't let you know unless you look in the history file...which I usually don't. It just does its thing in the background.

burnout426, Thanks for the suggestions!

I did as you suggested and all seems well. I had already reinstalled T'bird. None-the-less, T'bird still cant send emails that have attachments or forwards (that probably have an attachment).

Regarding "-> connection settings", I'd make sure Thunderbird isn't set to use a proxy."

It is set to use the system settings for proxys but when I set it to use no proxy it did not affect it (did not send)

Update: I did a Malwarebytes scan & a deep scan using MS AV software (took about 12 hours). The AV software found "Exploit:Java/Obfuscator.AH". It has been removed.

2 out of 3 mail software packages "seem" to be working reliably now (fingers crossed, both hands). Thunderbird does not work but Opera and the MS Mail app works. Not sure how it got there or how long ago. It probably was not the MS update.

Now to figure out T'bird.

Currently running another deep scan.

Thanks all! And seasons greetings.

I have 3 PC's. One is having the problem, the other two work fine. I can't say that it is a W10 problem but it is very coincidental that it started after the update.

2 nights ago I sent, Via Opera, an email with attachment at 1AM that did not go. The next day I noticed it went at 5AM (I think Opera is set to send/rec every 5 or 10 minutes). Yesterday I sent an email, Via T'bird, with attachment and it went right through. I sent another like it shortly after the one that went through and it did not. Last night I sent an email, via T'bird, that did not go and it never got out of the outbox. Forwarding mail also does not go though unless I delete the contents of the original.

Yes. Windows Home 1511 10586.86

Now that I have an outgoing log, I do not see any error messages. There is a lot of info and maybe I could deduce an error message but there is nothing like the error message Thunderbird created ... "Sending of the message failed. The message could not be sent because the connection to Outgoing server (SMTP) smtp.googlemail.com timed out. Try again."

Just a heads up for subsequent readers of this thread.

There should be a forum category just for Opera Mail. As I see it, Opera Mail users post in the Geral Opera forum which also includes the browser.

Update 2: I tried sending an email with attachment using the Windows 10 mail app and it does not send as well. I'm convinced the W10 update messed up something.

Update on actually getting the message sent... I noticed that an email with attachment did get sent about 4 hours after sending. I just tried sending with a small .txt file and it went through. A 1.36 .jpg sent right after did not get through. Again, both Opera and Thunderbird are having this problem.