Overriding 1099R box 2b (taxable amount not determined) does not make appropriate changes to 1040

[highschoolhank]

I received a 1099R with box 2b checked indicating taxable amount not determined.  Boxes 1 and 2a show the same amount.  I do not know why this box was checked since it was not in prior year 1099R's from this company.  As a result of this, form 1040 line 4a shows the taxable amount but 4b shows zero.  I thought I could correct this by re-entering the 1099R in step-by-step and indicating 2b was NOT checked.  I did this but nothing changed.  I verified looking at the 1099R in both "Forms" and step-by-step that the box was unchecked.  Why didn't unchecking the box cause 1040 line 4b to be updated?  Will I have to manually update 4b?

[Mike9241 · Accepted solution]

was this a distribution from an IRA? In this case, the taxable amount not determined box is often checked because the Trustee does not know if you made any nondeductible contributions to an IRA. Both amounts will be the same. If you did make non-deductible contributions the taxable portion will be computed on form 8606

[highschoolhank · Accepted solution]

Thanks for the response!  Traditional IRA.  No non-deductible contributions to it, but there had been non-deductible contributions to other IRA's so I'll see what happens after I have entered all 1099R's and get to the 8606.