Why did capital loss calculated by TurboTax 2017 Home and Business not carryover to TurboTax 2018 Home and Business?

Did you have at least a $3,000 capital loss on the 2017 1040?
If not, there is no carry-forward.

Did you transfer in 2017 data when the 2018 return was started?

Yes, line 13 on my 2017 1040 shows -$3000 and the long-term capital loss on the 2017 Schedule D, line 15 is over -$100,000.  When I look at "My Tax Data" for 2018 it shows many items were transferred to Schedule C.

OK so then we know you have a capital loss carryforward (due to -$3,000 on 2017).

And if it did not carryover from some reason this is how you can do it.

To enter your Capital Loss carryforward

Click on Federal Taxes
Click on Wages and Income
Click on I'll choose what I work on
Scroll down to Investments
The 2nd one is Capital Loss carryforward, click the start or update button.

You will need the 2017 return handy to pull off some numbers.