evolution needed for thunderbird? I renamed every running evolution file to disabled suffix: # ls -l evolution-*disabled -rwxr-xr-x 1 root root 10392 Feb 15 01:38 evolution-addressbook-factory.disabled -rwxr-xr-x 1 root root 79952 Feb 15 09:44 evolution-alarm-notify.disabled -rwxr-xr-x 1 root root 10392 Feb 15 01:38 evolution-calendar-factory.disabled -rwxr-xr-x 1 root root 14536 Feb 15 01:38 evolution-calendar-factory-subprocess.disabled -rwxr-xr-x 1 root root 101000 Feb 15 01:38 evolution-source-registry.disabled Also I changed my default MUA in `gnome-control-center` and I ran the following command: gsettings set org.gnome.desktop.default-applications.office.calendar exec icedove `icedove` is thunderbird uder Debian OS. **But my question:** Does `thunderbird` need to running some `evolution` commands?

No: `thunrerbird` and `evolution` are two separate projects/softwares/...

You may very well purge `evolution` from your system.