Why, during the final check, does it state that o (zero) is an unacceptable value for charitable contributions?

If you did not have any cash charitable contributions during the year, leave this field blank.  Do not enter zero. 

If you have a zero entered, go ahead and delete it and run the review again.  

1. Select Deductions & Credits at the top of the screen
2. Scroll down to Wrap up tax breaks
3. Continue through the screens until you see the screen titled Charitable Cash Contributions under Cares Act. 
4. You will be able to delete any cash contributions on this screen.

In the past, you were only able to claim a credit for donations if you itemized your deductions.

However, in 2020, you are able to take a $300 above the line adjustment for cash contributions made to a qualifying charity.  If you did make any cash contributions, you would be allowed an adjustment.  See the following link for more information.

Cash charitable donations information