Same problem, we think.
Completing the information was a bit complicated and confusing, but we'd gotten an all-clear in the TurboTax internal review. We had downloaded data from two Schwab accounts' 1099s. When we went to fill out Foreign Tax Credit info, TurboTax gave us two Schwab boxes to check as sources, so initially we checked both -- and it only filled in data from one of the 1099s. Confusing, but we proceeded to add the other one. TurboTax then lumped the two (both sources were RIC). Had to look up qualified dividends and LT gains on the 1099s to fill that item (not imported info), but okay. That took care of errors in the TurboTax internal review, but the return was rejected when submitted.
The problem is, despite the error message, we never saw a question about US Tax withheld in Step-by-Step, and there is nothing about it on the 1116 or the 1116 worksheet.
