Have you got anything like a slideshow screensaver running in the background, or anything else that might be stealing focus? Live tiles?

Many of the letter keys have particular functions in Thunderbird, but these shouldn't normally be active while you're composing. But if the focus switched to the main Thunderbird window while you're typing, chaos could ensue.

Have a look at the list here: https://support.mozilla.org/en-US/kb/keyboard-shortcuts

You'll see that a fair number of single letter keystrokes will do something.

Useful thought. Thanks. Don't have any background processes that I am aware of that could be stealing focus. (and if they do, the focus is fairly quickly returned)

The most problematic action is the message delete action, which would be the delete key. My fingers are no where near the delete key.

At points the software just seems to take over and not process my keystrokes in a normal fashion. If I notice that I am no longer in control I have to stop immediately and wait for control to return to me (about 5-10 seconds), or my keystrokes may be misdirected in Thunderbird.

It's like Thunderbird itself has a background process running that temporarily takes over and, among other things, wipes out my emails. (depending in part, I suspect, on what keys I hit while control is not on the email I'm typing)

Thanks for your suggestion, however. Is anyone else experiencing this Thunderbird-takes-over problem?

'Menu icon' > 'Activity Manager' would tell you if you had deleted an email. Are you sure they were deleted and not archived ?

Trying to ascertain what is occuring in background. When you experience the no longer in control of Write window composing area, at this point in time, is Thunderbird saving the email as a draft? Select 'Drafts' folder and check the time on the last save. Obviously you would need to check this each time it occurs in order to verify that saving to drafts was occuring each time you lost control in Write.

Good thoughts. I will double-check. Thanks! If Tb is saving as draft, I'm not sure why it would interpret the keystrokes as commands? (delete, archive, etc.)

re :If Tb is saving as draft, I'm not sure why it would interpret the keystrokes as commands?

It shouldn't, but I'm trying to ascertain what is always occuring at the same time to shed some light on this issue.

Other things to check: Is Thunderbird checking for messages every time the problem arises? This info will also be in the Activity Manager.

Do you have an anti-virus product scanning emails? What happens if you access the AV and specify not to scan any Thunderbird folder on startup or incoming/outgoing mail. It will still scan if you open attachments and thunderbird does not show remote content by default.

If it were an AV issue, why would it be taking the keystrokes over to the main window. How do I determine where the TB files are stored, so I can exclude this from the AV scan?

I'll be honest, I believe that some function in TB is sending the focus to a different window. (Sometimes if I stop typing right away, it "freezes" up and then the focus comes back to the email composition window. So, I interpret this to mean that while it was doing whatever it was doing, it didn't have keystrokes in the buffer to process in the other focused windows it was circling through, so it was able to proceed with it's task and wind up back in the composition window.)

But, if this interpretation is correct, whoever wrote the module/routine that causes (initiates) it to go off and do something else, didn't find a way to protect the keystroke buffer from activating in the other windows that they had it cycle through (most often the main email list window))

I can't be the only one having this problem. This could easily kill TB. I've lost over 25 emails that I know of in the past 2-3 months, half of which were critical and I either couldn't recover, or had to have the sender re-send... And, they are considering TB to be incompetent open-source software. I am at a loss to dispute their assessment.

It is just such a pain after a decade to move back to Outlook. But, will do it when I can carve out the time. Dx!Q darn

I've developed software for national enterprise firms. Am willing to pay for software that works. Strange thing is that TB worked fine up until this past several months. Someone wrote or modified a module that destroyed basic keystroke integrity... the foundation of trust with the user.

(sorry for rant... just so sad to have to leave. extended patience now gone. too much destruction)

It is possible that as you are typing, you are accidentally hitting the Ctrl or Alt keys. Then whatever key is pressed after that gets interpreted as Ctrl or Alt that character.

This can especially happen if you have turned on "Sticky Keys" in Windows. All Control Panel Items\Ease of Access Center\Make the keyboard easier to use

That can cause chaos.

No, Bruce. Not hitting Alt or Ctrl or StickyKeys. But, a good thing to have checked.

Did you try what happens when running Thunderbird in Safe Mode?