Options->Agenda->first day of the week

Thank you for your answer. But that does not help me, as I can't find any "Options". At least in the menu bar, or the Thunderbird menu.

All I can see in the menu bar is: "File", "Edit", "View", "Go", "Message", "Events and Tasks", "Tools" and "Help". I have been through those and could not find what I am looking for.

On the top 'Menu Bar' which has "File", "Edit", "View", "Go", "Message", "Events and Tasks", "Tools" and "Help". 'Options' is located in the 'Tools' sub menu near the bottom.

Otherwise it located on the 'Mail Toolbar' which has 'Get Messages', 'Write', 'Chat', 'Address Book', 'Menu app icon (3 horizontal lines)' and 'Global Search'. Click on the 'Menu app icon' and select 'Options'

Options opens in a new tab, then select 'Calendar' to see settings. see image.

Thanks, I've opened the 'Menu app icon (3 horizontal lines)' in the 'Mail Toolbar' (which in my case is located on the right of the 'Global Search'. And then I could not find 'Options', but instead I have 'Preferences' which has the same icon and is located at the same spot. I've done that many times before and I could only see 'General', 'Composition', 'Privacy & Security', and 'Chat'. But I've opened the preferences again and now there is the 'Calendar' sub menu that has appeared. I don't understand , but it works, so thanks.

re : I could not find 'Options', but instead I have 'Preferences'

When responding to any question it is assumed the person is using a Windows OS as they are the most common. It would be helpful if in future you could mention the OS you are using. eg: MAC , so reponses can be tailor made to suit your needs.

If you ever look for potential solutions for issues and you see the word 'Options' then substitute with 'Preferences' and you will find all other info is the same.

good to hear all is ok

Sorry for not specifying the OS. It was Arch Linux. I assumed Thunderbird is the same on every OS. I have just learned that differences exist.

Thanks for your help.

Hi, Running Thunderbird 78.7.1 (64-bit) on Ubuntu 20.04.2 LTS. Under preferences there are no calendar references. General, Composition, Privacy and Security, and Chat. On the bottom or the sidebar is Extensions and Themes. I cannot find any calendar settings anywhere. The only line mentioning monday in config editor is "calendar.week.d1mondaysoff;true" ???

OK, It looks like the way to get to calendar preferences is to open preferences, which will not have a calendar reference, close thunderbird, reopen thunderbird, and the calendar option is there. I'm going to try this again.

It seems that once those hoops have been jumped through, the calendar option persists.

This is a fresh install of ubuntu. It appears there was no calendar option in preferences until I closed thunderbird with the calendar and preferences tabs open. When I reopened thunderbird there was and still appears to be a calendar option in preferences.