You sure made sure that conversation ended by not replying. Makes me wonder if I should reply here.

I really see no issue here. The master password is used to decrypt the password store on the local disk, so I see no issue with it being requested when you startup offline as it is being used on the local file system not remotely.

To delete all account and master passwords, delete or rename these files in the profile folder, while TB is closed: key4.db, logins.json and cert9.db.

http://kb.mozillazine.org/Master_password

Hello Matt & Others, Firstly apologies. For some reason I never received Emails that anyone responded ergo I never logged back in. This time I received a few Emails alerting me to replies and here I am. The problem I having is still the same. I open T-bird and get that pop-up and close same. As I reply to my corespondents the pop-up keeps coming back, I close it, it pops back, on and on and on. If I open T-bird in offline mode. I still get the pop-up once, close it and the merry go-round continues. I just don't understand why the pop-up will just close and not return until I try and send an Email. Even if I turn off my modem or disconnect from the internet, T-bird keeps popping up the request for a password over and over. Thanks for the help, now that I know how the system works I'll keep an eye out for a notification. Thanks again Tom

Thunderbird tries to send immediately. That is how it works. So it wants the password for the SMTP server so it can send the mail. When in offline mode the send button becomes "Send Later" and the outgoing mail is queued in the outbox folder pending Thunderbird going online again, or you exiting the program and get prompted to send mail now.

If you do not want to see the dialog in online mode use send later not send for your outgoing mail.

Ctrl+Enter (Send) Crel+Shift+Enter (Send later)

Hello Matt, Thanks, seems to me I've tried that before. But that was many versions ago. I set T-bird up in offline mode. The little twin-monitor icon has a red slash and hovering over it says I am in offline mode. The "Paper Airplane" icon (Send) now says send later. I'll try and compose a few Emails and make sure it doesn't pop up again. Let me have 24 hours and I'll let you know and close out the thread. Thanks again Tom P.S. When I log in here there are two questions I sent over a year ago and I ignored them as I explalned. Can they be deleted or removed? Again my thanks, and Thank-You for your service as the moderator. I started with version 1 of Netscape.

Hello all, Since January 2nd 2020 I have booted Thunderbird in "Offline" mode. Everything works fine, EXCEPT that darn pop-up asking me for a password while I'm composing a message offline is still happening.

I have updated to the latest version of Thunderbird 68.3.1 and have checked the "Offline" option when it asked me to select a profile which is "new" to me. Yet even though I am offline and I have not got online to download new messages and am answering messages from my previous session offline. The "popup" password dialog box keeps popping up.  Is there a way i can direct this to the people who make changes in Thunderbird. If this "popup" cannot be stopped at the very lest perhaps a alert sound?

Thanks for any and all help. Tom

The master password prompt in your first picture does not depend on the offline/online status, as already mentioned, as it is purely to protect access to the locally stored passwords. If you want to reset or remove the master password, remove or rename the three files described in my first reply.