Unfortunately Coinbase Pro's API include conversions of USD into USDC which can lead to a warning trade appearing on the review data step. In order to resolve this warning, you can follow the steps below.
UPDATE 3/16/2020 - CryptoTrader.Tax can now read in the conversions on the accounts.csv file from Coinbase Pro. If you have conversions, we suggest importing all trades in through this file to avoid warnings. Here's the guide.
Check the accounts report on Coinbase Pro to see if this is effecting you. Download this report by going to the Statements page, hover over the Generate button, and click on Account.
When exporting, make sure to select All Accounts and choose a date range which covers your full trading history.
After downloading this file, open it up and check for entries with the type as conversion. A single conversion will take up 2 rows like shown in the picture below:
Enter each conversion as a single trade using our Other Exchange template in order to resolve the warning. In the image above, the manual template would be filled out with the following info:
When filling out the Other Template, copy and paste the timestamp exactly how Coinbase Pro has it on their file. This will prevent Negative Balance Warnings from appearing.
Import the newly created CSV file on the Other Exchange tab in order to resolve the warning.