TurboTax says that my 1099-R box 16a state distribution amount should not be less than state tax withheld. On my 1099-R, box 16a is blank. What should I do?

You should enter the amount from box 1, gross distribution, in box 16a, that is what should have been listed there.

So it's okay if I enter a number that isn't actually there? I feel like that is cheating/lying.

You can ask your company for a corrected W-2 form but it may be difficult to get them to do that. But clearly if you had tax withheld as reported in box 14 on your W-2 form, there would have to be wages from which it was withheld, which should be reported in box 16. If your tax does not change when you make the entry then it will not pose a problem when you file your tax return.

I called TurboTax for help.

The expert had me delete the two 1099-R forms that had the problem, and enter them manually. This didn't solve the problem. She then had me enter the amount from box 1 of each form. This did solve the problem. TurboTax software has a problem, in any case, but at least this workaround worked.

BTW, this took over an hour and a half of my time and her time... B-O