Similar to others, I hit the large historical data wall with my calendar today. The calendar works fine with yesterday's file — add a single transaction to the register and it stops working.
Other users have hit the same limit with identical results. (search same discussion title)
The resolution appears to be delete (years of) historical data and the calendar will function.
Noting that tech support recommended marking historical transactions as "clear" so that each and every reconciled transaction doesn't need to be confirmed for deletion.
Penalty for being a decades long customer…