I got a CP200 letter from the IRS saying that I owe almost 4,000 due to an error on my 2018 return. I think that Turbo Tax made a calculation error. Advise?

[lauramimms]

It looks like the Mortgage Interest deduction amount was doubled. I would not have doubled that number on my own

[Mike9241]

TT enters nothing.  haven't seen others reporting that TT double up on their mortgage interest deduction.  you can file a claim with TT, but honestly, it looks like it's your error. In addition, you should have review your return before filing. if you had you would have noticed the interest was doubled.  in any case, you will have to pay the taxes, TT will only pay the penalties and interest if the issue is caused by their calculation error. 

here's the link for information on filing a claim

https://ttlc.intuit.com/community/choosing-a-product/help/what-documents-do-i-need-to-submit-a-claim... 

[JeanneLO]

@lauramimms

The link provided above is the correct one if you believe you need to file a claim with TurboTax on your prior tax return:

What documents do I need to submit a claim under the TurboTax 100% Accurate Calculation Guarantee?