I customize my toolbar on Thunderbird for ease of use, as I don't use many functions. All I really need is reply, reply all, delete and my calendar.
The problem is every time Thunderbird updates, it resets to the default toolbar. Is there a way I can save my tool bar so it does not default to the default toolbar every update?
The problem you have is the same I had time ago. Tones of options really don't need.
Once you configure all preferences and customization, backup this files from your profile folder and restore later:
extensions.json --> some extensions and languages, activ/deactiv, themes, others. prefs.js --> preferences & config session.json --> appearance xulstore.json --> appearance