If you have Capital Gains being reported on Line 12700 of this year's tax return, you can claim your Capital Loss carried forward from last year. You'll need to enter the loss (instructions in the link below) and the amount you are able to claim will show up on Line 25300 as Net Capital Losses of Other Years.
This link explains how to deduct your losses: How do I deduct losses?
Turbotax online review states that there is insufficient funds in my previous years capital losses to claim application against this year’s capital gain. My 2018 tax assessment indicates that there is more than twice this year capital gain. Is this a problem? Can I ignore the turbo review observation and file my return?
You have to enter the net capital losses carry forward in your return to be able to apply against our capital gain:
Enter your Net capital losses and the amount you wish to apply as shown in the following example from TurboTax Desktop:
The software will calculate how much available in every year and how much you can claim.
I hope this was helpful