The Turbotax informational post says there is a 2,250 transaction limit in CSV, and CoinTracker says they aggregate to that number or lower as part of their partnership with TurboTax, but the online entry limits to 1000.
Switch to the downloaded version which has a higher limit ...
You can move your Online file to the Desktop program and continue without paying for Online or needing to reenter your info. In the Downloaded version you can "cheap out" and use the Deluxe ( or Basic if you don't need a state return)...
To continue in the desktop version see this…….
https://ttlc.intuit.com/questions/1901476-how-do-i-switch-from-turbotax-online-to-the-turbotax-software
TT FAQ on Crypto :
If TurboTax won't accept your CSV file, proceed as follows (this is the simplest way).
Adjust your csv files so the columns are in the same order as on Form 8949.
Put a header with your name tax year and SS Number
Use the summary option and then you can mail in the printout of the CSV files.
See the TurboTax instructions that will pop up.
You would use Category C and/or F since you don't have a 1099-B.
At tax time, you have the option to summarize your transactions by Sales Category.
IRS requires C/F details to be listed on your own Form 8949,
or on your other forms (e.g. spreadsheets) which have the same information and in the same manner as Form 8949.
Either way, if you choose to summarize, you have to mail the transaction details to the IRS within three business days of IRS accepting your e-Filed tax return. unless TurboTax Online asks you to attach the PDF file immediately.