Hello there hfjabre. We have read your message. We try to help you.

What calendar are you using? Do you use multiple calendars in Thunderbird? Deleting all your entries.

https://support.mozilla.org/en-US/kb/calendar-updates-issues-thunderbird

https://support.mozilla.org/en-US/kb/changing-calendar-

to delete the items saved from your calendar that you might have saved in a backup, also delete them from your computer.(Thunderbird map). you can delete and reinstall the entire program.

To cleanup manually, rightclick on any calendar and choose "purge Events...". Select the Calendar from the list, set the time you want to keep and press 'cleanup now'. To enable/disable autopurge use the setting, set the settings for each calendar and apply separately.

Greetings Firefox volunteer.

Hello there

how did this question arise to us? Is it that Lightning plugg inn crashed when starting the Thunderbird program?

Lightning could also be removed when installing multiple calendars, the other has to wait until the other is installed or removed.

Also the option that it is related to other software installed for other components on your machine pc. This same rule may persist until they are updated or completely removed as mentioned above.

check this out if you can.

Is the option delete them one by one and reinstalling the Software again there? Then use it.

Greetings Firefox volunteer.

On the Calendar tab, enable Find Events under Events & Tasks, choose All Events on the filter drop-down, select the events, then Delete key.

Thanks, sfhowes, for your input. I knew that but surely there is an easier, more efficient way of doing it.