Deductions & credits

Please try these steps:

1. Click Deductions and Credits
2. Select Review/Edit
3. Click Edit to the right of Standard Deduction
   ​​Click OK, Sounds Good
4. Click Wrap Up Tax Breaks
5. Click Continue
6. Make sure that $300 is filled in and then click Continue
7. Click Lets Keep Going

If the error persists, then go through the next work around.

Here is the second work around for claiming the Charity Deduction:

1. In TurboTax select Federal in the panel on the left
2. Select Deductions & Credits at the top of the page
3. Under Your Tax Breaks - Charitable Donations 
4. Click START to the right of Donations to Charity in 2020
5. Click YES
6. Click ADD next to Money
7. Type in the name of the charity that you donated to
8. Type the amount of the donation
9. Select Done with Donation
10. Select Done

Now the deduction should appear on Line 10B and in the Charitable Contributions screen.