Check the settings for that account (go to Tools > Account Settings > Copies & Folders). Tick the Place a copy in, select Other then point to the Sent folder of the affected account. Do the same for the Drafts & Templates section. At the bottom, you can tick the box to get a confirmation message every time a draft is saved. You may also want to add Tbird's profiles folder to your security software's (antivirus program) exclusions list.

Thank you. That seems to have worked.

You're welcome.

The solution makes sense, but it did not solve it for me. I use a Mac running OS 10.14.6 and no anti-virus software and TB 68.9.0. It's done it more frequently since this last update, but it was also periodically doing it prior. Wish I remembered for which version it started being a problem.

It's now doing it for sent messages too. I'm attempting to attach a screenshot. And weirdly enough, someone emailed me to another address saying their message had bounced back to them saying my mailbox was full, which it shouldn't be. Meanwhile, I had received the message.

It's now doing it for sent messages too. I'm attempting to attach a screenshot. And weirdly enough, someone emailed me to another address saying their message had bounced back to them saying my mailbox was full, which it shouldn't be. Meanwhile, I had received the message.

Sounds like something else is going on with your email account on the provider's server side and not Thunderbird. Who is your email provider? The fact that the delivery subsystem thinks your mailbox is full suggests this is a problem with your account's side of things. I'd get in touch with your provider's support team and have them look into your account's setup. Thunderbird has been saving copies of sent and drafts just fine here, as long as it is properly configured. Each email provider has there own settings of how sent items are handled. For example, Outlook.com, Gmail and Yahoo's outgoing servers automatically save copies of sent items in their respective sent folders, so in Thunderbird you disable those settings for those accounts or you may end up with duplicate copies of sent items.

For experimentation purposes, create a local folder for sent items, configure Tbird to save them there then send a test message and see if the copy is saved in that folder without issues.

This morning, after many attempts, i've UNCHECKED the flag (Copy the message in:) and it works correctly O.O' ...(i can find the message in the sent folder on TB and on the web interface too). Don't know why but it seems to work anyway.

This morning, after many attempts, i've UNCHECKED the flag (Copy the message in:) and it works correctly O.O' ...(i can find the message in the sent folder on TB and on the web interface too). Don't know why but it seems to work anyway.

Each email provider has there own settings of how sent items are handled. For example, Outlook, Gmail and Yahoo's outgoing servers automatically save copies of sent items in their respective sent folders, so in Thunderbird you disable those settings for those accounts or you may end up with duplicate copies of sent items or failures to copy the message. The smtp server decides how to handle sent items. If you want a copy to be saved locally on your computer instead, then you should adjust Thunderbird's setting accordingly and point it to a local folder.

Technically this question is NOT answered!

The ops problem may be resolved but it tells none of us "WHY" which is the original question. I realize there may be many "WHYs" but nothing here helps us in any way determine what IT actually is.

The answer should be telling us how we can identify the actual reason this is occurring, not only the most common. For example, we should be able to see a log somewhere indicating exactly what the issue is, is it network, protocol, memory, storage, security related etc.

In my case, I found the "error" console and there is a single error that keeps incrementing every time I click "retry" on the Save Message dialog and the message is very critic only mentioning my graphic card and a FBO texture target?

OpenGL compositor Initialized Succesfully. Version: 2.1 NVIDIA-10.18.5 378.05.05.15f01 Vendor: NVIDIA Corporation Renderer: NVIDIA GeForce GTX 960 OpenGL Engine FBO Texture Target: TEXTURE_2D

This is not very helpful. Seriously, where are the real error logs showing us what is going on behind the scenes? Can we crack this nut open?

p.s. Successfully is spelled wrong.

Here you go https://www.lifewire.com/pop-imap-smtp-traffic-thunderbird-1173156

Thanks Stans but sadly the instructions at that link appear to be incomplete for all 3 operating system examples.

For Windows, step 7 is completely blank and some of the other commands also don't appear to be complete.

For MAC and Linux it's similar. MAC specifically, the path for the NSPR_LOG_FILE comes back no such file or directory and the parts about logging multiple protocols at the same time also appear to be incomplete or incorrect.

For example the path shown for MAC is /Applications/Thunderbird.app/Contents/MacO which is missing the S completing the folder path but then again, what is this supposed to do...typing a folder path at the command prompt and pressing enter does nothing but say "is a directory". I believe this should be a full path to where the log file should be stored and doesn't correlate to the next step showing it should appear on the desktop in which the path would correctly be ~/Desktop/whatever_my_log_file_is_named.txt.

I'll dig around and see if I can find another example now that I know some of the commands I can use them in my search terms. I'll post back if I find something more complete. Thanks.

Curious also, when I attempt to move the saved "sent" emails from my "local" folder to my server's (IMAP) "sent" folder, I receive a popup in the upper right corner of my MAC's screen which states:

"The current command did not succeed.

The mail server for the account blahblah@blah..."

Appears to be truncated, cutting off any remaining information that *could* be helpful in sussing this out. Clicking on the notification just makes it go away. It would be nice to see the full explanation if by any chance it actually provides any real context as to the "WHY" this is occurring.

Essentially my IMAP account (of which I've been using over a decade with TB) decided 3 days ago to no longer save drafts or sent emails but I have yet to find a way to discover WHY.

One of my comments went to moderation for some reason. Essentially the link provided for logging instructions is incomplete for all 3 operating system examples. One of the steps is just blank.

See https://wiki.mozilla.org/MailNews:Logging

Turns out all I needed to do was log into my webmail and see that my sent and junk folders are now capped at 2gb. I never use webmail to otherwise know this and maybe my email server wasn't providing the reason to TB. Maybe it was. I'm over this now but at least I have something to check back on if this type of thing resurfaces. Thanks.