I've tested Thunderbird's supplied send later and it works fine.

If you are using the send later addon and are having problem, you'll want to report problems to the author at https://github.com/Extended-Thunder/send-later/issues

Thanks, Wayne. I am using a MacBook Pro running macOS Catalina (version 10.15.7). Since upgrading to TB 102.1.2 yesterday, I have had a number of problems.

First, shortly after I opened Thunderbird, and after everything seemed OK with my various mail folders, I had an experience where clicking on a message (ANY message in ANY folder) yielded only an empty space where the contents of messages are usually displayed. I quit and restarted TB, and that problem corrected itself.

Then, when I tried to send a message "Later", using the File/Send Later option (not an addon), as I habitually do so that I can give messages a once over before sending and make corrections, if needed, nothing happened. The usual pop-up window (or whatever the terminology is) that allows one to correct detected spelling errors did not appear and the message just sat there, unsent. Then, at some point later in the day, the "pop-up window" began to appear briefly when I would try (as an automatic reflex) to use the "Send Later" function, but would instantly vanish, again, with the message left unsent. At one point just a little while ago, the Send Later spelling review window opened up and sat open on the screen for a brief moment, before disappearing. I can work around this problem by saving messages as drafts and reviewing them in the Drafts folder, but that is a pain and doesn't work well if I have a series of messages to review and edit (all to the same recipient) and I want to preserve the order once all revisions have been made. I'd be grateful if you could share any thoughts you might have as to what is going on and how it might be corrected.

I had thought about trying to drop back to TB 91, but I'd just as soon not run whatever risks might be entailed in doing that (I am not sophisticated enough to feel confident in my ability not to make some sort of mistake). Also, I can appreciate other improvements that have been made in the present version (at least having seen the new Address List functionality).

Actually, there is also a glitch, in my mac environment at least, in one Address List function, which occurs when I left- or right-click on an e-mail address and am given the option to "Add to Address Book". Whereas the "Copy Email Address" function works, absolutely nothing happens when I try to choose the "Add to Address Book" option. (I can work around that easily enough by copying the address and then manually opening the Address Book; but I am in the habit of using the "Add to Address Book" feature, and find the reflex hard to break.)

Do you have any further thoughts you might be able to share about how I might handle the situation? I am behind in upgrading my macOS (after having had to recover my entire system from backup after a previous mac upgrade disaster). Could that be a part of the problem (using an older macOS version)? I have restarted TB several times; that doesn't seem to do anything. I haven't yet rebooted my computer (as I have a lot of open desktops that would take time to close down in an orderly way).

Thanks for any help you can provide.

Peter

One more comment: This time when I tried to send a message using the "Send Later" function (I just tried automatically, forgetting the ongoing problem), the spell check window actually opened and let me go through the spell check items. However, when I clicked on "Send" at the bottom right of the window, the window gathered itself up and disappeared; however, nothing happened. The unsent message in the compose message screen stayed on the screen and nothing appeared in the "Unsent Messages" folder. I then successfully sent the message by clicking on the "Send" icon at the top left of the compose message screen.