Completely disable calendar

Why can’t I choose what happens when I open a .ics (calendar) file? eM Client overrides the system default and opens its own calendar dialog instead.

There is a Sleekplan suggestion to be able the add Calendar.ics invitations “directly to the Mac OS Calendar” when you receive them in eM Client which you can vote for below

There is a way you can currently add them to the Apple iCal when you get a .ics Calendar invite as @asn advised in his post below on that topic.

Also a frustrating thing is that invites from Microsoft user has no .cal file attached so I cant even save that to disk to open later.

I don’t have that issue from other friends Microsoft Outlook or Gmail Calendar invitations, so could be your senders Calendar just eg: dont provide the cal .ics file when the invitations are sent to you.