Hello there We have read that message. We try to help.

Some of the reminders are not visible.

It might be time to check for some settings : Enable reminders Set reminders. Show missed reminders. Check for updates for that calendar . Be shure thane that calendar settings are not hidden. Having calendar extensions?check for their updates.

Hello there

Other fix for that reminders ain’t there.

Got o view > calendar>Calendar pane>Calendar list>Activate it.

If that calendar is locked right click on that calendar select properties then uncheck the read only box that appears there. It might be solved now.

Be sure that there are no other calendars. Delete them if possible.

Greetings google Thunderbird.

Sorry but none of these answers worked except they did put me in the right location.

Checking all the settings I noticed my old email address was still listed in Calendar Properties. I just decided to change it to my new address. I have been using this new address for over 3 years. The problem with reminders started just 7 days ago. Must be due to an update of something. I know Thunderbird only updated sometime since Friday. I don't have any addons.

Anyway it is sorted.

Sorry but none of these answers worked except they did put me in the right location. Checking all the settings I noticed my old email address was still listed in Calendar Properties. I just decided to change it to my new address. I have been using this new address for over 3 years. The problem with reminders started just 7 days ago. Must be due to an update of something. I know Thunderbird only updated sometime since Friday. I don't have any addons. Anyway it is sorted.

I have the same problem, but nowhere can I find calendar properties to check email address, where is it? Since the update to 140.1.0esr I am not getting most of my reminders, just the odd one or two and even those are not staying and disappear before I have a chance to dismiss them

Should have been more specific.

I changed my email address in my Mozilla settings online. I had quite a search to find where this is done.

When logged into Mozilla do a search for "Change the primary email address on your Mozilla account".

Also go to Thunderbird Settings/Calendar and make sure the box for "Show missed reminders for writable calendars" is checked.

The latter part "Show missed reminders for writable calendars" was suggested previously elsewhere, and I found it unchecked, on ticking the box, closing and reopening Thunderbird all the old reminders came up, so thought it had cured the problem but next time of opening, nothing, no reminders, all I am getting at present is one reminder I set a few days ago, one other comes up daily but disappears without my dismissing it

As to changing the primary address I am none the wiser, searching as you suggest in Help from Thunderbird came up with nothing useful, tried the Help from Firefox (which I assumed would be the same but no) it came up with a few but there has never been a connection or difference as far as I am aware, I use my main email for TB and another for most other things such as this Mozilla help

It has never been an issue before so why now?, TB is working as it should, but Lightning isn't, what would be the connection between Lightning and Mozilla support/help? or am I missing something obvious?

So I am loath to change the Mozilla log on email address to my main email address unless theres a good reason to do so

What I said was "I changed my email address in my Mozilla settings online". Not Thunderbird. Not Firefox. MOZILLA ONLINE.

Please reads this slowly and carefully "When logged into Mozilla do a search for Change the primary email address on your Mozilla account". That is a direct copy of what I wrote. I really hate it when people have preconceived ideas and don't bother to actually read what is written.

This is online, in your Mozilla online account. Online and Mozilla web account. I thought that would be clear. You are not making changes on your computer! You are making changes on your Mozilla web account.

So, go online, log into your Mozilla account (online) and then type the search line I wrote, into the Mozilla Search box (online).

This is how I changed my email address in the Mozilla Online Account. Whether this is what you need to do I have no idea. I am just clarifying what I did. The address change may have had nothing to do with the original problem.

Well thank you Mr Angry ;-)

It seems you don't read replies either, I asked what connection there would be between a Mozilla log in email and Thunderbird/Lightning?

As far as I can see, none

I also explained why I am loath to change the email address used for Mozilla, keeping a separate email address for all and sundry keeps spam to a minimum

Until this update Lightning calendar reminders worked as expected, now they don't, so something in that update has caused this, I am not the only one with the same problem, I cannot see a connection between a Mozilla log in email to Lightning all of a sudden stopping working

PS I was logged into Mozilla when I did the search

You asked where to find the email address change location. "but nowhere can I find calendar properties to check email address, where is it?" (Quote from your first post)

I simply told you where it was. What you do with this information has nothing to do with me. You asked where it was and I told you. The email address connected to the calendar is set in your Mozilla online account settings.

You complained

"It seems you don't read replies either, I asked what connection there would be between a Mozilla log in email and Thunderbird/Lightning?"

Read the last paragraph of my previous post. Take note of "I have no idea". Does that give you some idea of how much I know about what you wanted answered? I believe I did answer you.

You still cannot find where this email change can be made?

While typing this post, I alt / clicked on Mozilla Support (above). In the new tab I copied my search term "Change the primary email address on your Mozilla account". First result of 30 was the right one. Click on it and full instructions are given.

Other than this I have no further information or knowledge that can assist you. Like you I an just a user trying to find answers.

Thank you again for your input

I have been a Thunderbird user since Outlook Express ended, must be some 15 or 20 years ago, thankfully I have rarely had a problem (which are thankfully rare in themselves) I couldn't solve myself

I am well aware these forums are user to user, so even more reason to be polite to each other wouldn't you say?

Its a pity Mozilla don't have a help itself but understandable

As a PS to my previous posts re missing reminders, one reminder recently set comes up every time still, others do not, even newly set reminders, last night at approx 6:30pm, without even touching the keyboard, up sprang the reminders for that day, the day to come and the day before, I thought something must have been found and changed in Thunderbird or Lightning, but no, this morning back to normal, just that one stubborn reminder

So its still not resolved, hopefully Mozilla will fix the problem sometime?

I just realized this morning 9/9/25 that I wasn't receiving Notifications. How long I hadn't been receiving them I don't know. I thought that they might be appearing in Widoze 10 Notifications. They weren't. I thought that in the latest update that Mozilla had moved the notifications without telling us. I hope they don't think to do this since I have my Windoze Notifications set to Focus Assist and I never look at it. When I start Tbird I expect to see Notifications at the top of Tbird, not have to look for them somewhere else. I hate it when something breaks and I didn't do it. (Enough of my rant).

I was able to fix this problem on my laptop.

I clicked on Tools. Settings. Calendar. Scroll down to Notifications. Click Button labeled +Add Notifications. Notifications popped up on my screen. To double check, I quit Thunderbird, then restarted it. The Notifications popped up automatically.

I will watch to see if this is permanent.