I recently did a clean install of Mountain Lion (upgrading from Lion). Exported my calendars to a "Calendar Archive" on Lion and then imported them on Mountain Lion.
Maybe I broke something, but I don't see a way to add new calendars "on my mac". The only option i have in File | New Calendar is "iCloud" (which is not what i want). Is there a preference I'm missing somewhere?
A possibly related problem: syncing with iCloud seems to be broken. I get a triangle alert icon to show there has been a problem (but there is no clue what the problem is). I spent and hour on Google hunting but couldn't find a place to look for logged error messages.
Best Answer
Apparently you'll have to:
This will make the new calendar, under On My Mac to remain.