What's your version of TB? There are versions of Lightning and Send Later for TB 60 and 68, but only 60 for ReminderFox.

It is 60.8.0 (32-bit). (Not sure why it is 32 bit.) Is that out of date? I thought TB kept itself up to date. Big jump from 60 to 68. Or so it would seem. Should I update or will my add-ons eventually update themselves and start working again on this current version?

Now TB has hung twice since my previous message, requiring that I kill the process.

If I upgrade it to V68 64 bit will Lightning still remember my calendar entries? Will I need to re-enter all of my email accounts and RSS feeds and such?

TB 60.8 32-bit is the latest version in wide release. TB 68 is in limited release, and users on 60.8 won't be auto-upgraded until 68.1 is released. The jump from 60 to 68 is only to stay compatible with Firefox ESR versions. A major TB update, 52, 60, 68,... is released about once a year.

If you upgrade to 68, Lightning should read your existing data, and all mail and RSS accounts should be preserved. But unless you really need a new feature in 68, why not play it safe and wait until the upgrade process from 60 to 68 is refined and verified?

OK, I will definitely stick with V60. But what about my add-ons? Did the Windows update break TB or did it make the add-ons incompatible or what? Do I need to do something or wait a day or two for it to resolve itself?

What add-ons are you referring to (names and versions)? I don't think a Windows update has any effect on add-ons.

Lightning 6.2.8, ReminderFox 2.1.6.6, and Send Later 6.4.6.

Windows did a huge update. Kind of like going from Windows 7 to Windows 8, only Microsoft decided to just always call it Windows 10 forever and sneak in the upgrades. Everything runs under Windows and so Windows can potentially affect anything. These huge updates always break something, and not always the same thing on every computer.

I was hoping to find out if this is a known problem since the big update and what to do about it. Maybe wait until a fix is discovered and the add-ons start working again; maybe figure out how to backup the save add-on data and then reinstall Thunderbird; maybe go looking for some different calendar/reminder solution entirely. I really like how these add-ons work with TB, especially Send Later, and I'd hate to lose them.

I fixed it. While the add-ons all looked normal, current and loaded and such in the Add-Ons Manager there was no other sign that they even existed. I had already tried updating them specifically, but was told that they were all up-to-date. So I searched for each one and clicked the install button and re-installed them all over again. I may lose my Lightning events, haven't checked yet; but there aren't too many right now and I can reconstruct those from emails if necessary.

Both add-ons updates and Thunderbird updates do not lose data (unless there is a bug of course).

But you do backup your data on a regular basis, right?

I do nothing on a regular basis. Life would be too boring. I have regular backups setup on my machine, but the nature of those things is that you never know they are broken until it is too late. I also do occasional manual backups just for insurance. And if it is possible to extract just a single file or directory from either of them, I honestly would not know how to do it, or if it is even possible.