No evidence of calendars at all since update to 45.5.0
Thunderbird updated itself to 45.5.0 and since then my calendars have disappeared. The provider for Google Calendar is still installed, but I can't find any menu item or button to display the calendar tab. (it is always possible I closed the tab, but I don't find anyway to recreat a calendar tab)
Running a 64 bit version of Windows 10
Peter King
Alla svar (1)
Provider only provides a connection between Lightning and online calendars, and it seems you are missing Lightning.
I usually get things straight by uninstalling and removing Lightning from Tools|Add-ons|Extensions then reinstalling it.