Hello there We have read the question We try to help you

What else can you do with this add-on? Can you move them and or save them somewhere else? Transfer it to an erasing program or to an external USB? After these actions, none of these add-ons have ever disappeared or simply been removed?

And what version was this previous Thunderbird app/software of yours after your last one and was your update manual?

Are your add-ons really up to date? Can you update other add-ons today?

Greetings Firefox volunteer

Hello there

Your add-on that you propose to us no longer exists, one of these is still present but is no longer running.

You can choose a new selection from our Thunderbird add-on database.

How to remove these outdated add ons? It looks like you have to hit the delete button?

Greetings Firefox volunteer

Hello there

These icons may eventually disappear depending on what kind of operating system you have and also what kind of computer you use.

Do you have any duplicates on your computer that you should have already deleted after this update to the latest release of Thunderbird software?

try going to your profile folder on the pc itself , where these add ons and extensions are stored in your previous folder.

check whether there is a similar add-on or extension available. Has your extension or add-on been assigned an unknown name in profile storage or does it already contain one? To be sure, open the add-ons you found in an editor where you can see the entire add-on or a description of it.

Try to delete them of try to delete them all. You can also delete these addon files in one time.

Does this extensions and addons folder still have the same name or has it been changed to a number-like code?

Greetings Firefox volunteer.

Hello there

files may also have become corrupted while installing or downloading a new update for your Thunderbird program.

You can look for a solution to influence this issue and make it work again.

look in your profile folder for the compatibility.ini file try clearing it if possible and restarting the Thunderbird application. This will create recovery under the folder that recovers or deletes leftovers from damaged folders.

Greetings Firefox volunteer

Both add-ons I mentioned do still exist, although the safelink one has a different name in the market compared to when installed

https://addons.thunderbird.net/en-US/thunderbird/addon/unmangle-outlook-safelinks/?src=search https://addons.thunderbird.net/en-US/thunderbird/addon/nestedquote-remover/?src=search

I don't understand most of what else you're asking, but I did note in my original post that I had tried removing and re-adding the extensions but it did not fix things.

Removing compatability.ini had no effect, but I also shouldn't think that would cause the "Add to Thunderbird" button in Thunderbird to do nothing either.

Can you post a screenshot of what you seen when attempting to add the addon? I just selected the nestedquote remove addon with no problem.

It would not show anything meaningful. All that happens is the button depresses. There is no warning, or message in the status bar