Lump sum tax ck issued half of it taken for taxes. Can I ask for the full amount (haven't cashed ck) so that I can roll it over Roth IRA?

Lump sum tax check?

Is this a tax refund? What is the source of the funds?

You have to have earned income to contribute to a Roth IRA.

Or is this a required minimum distribution (RMD)?

Www.Bogleheads.org is a very good forum for getting expert financial advice. But you need to give clear and precise information for any of us to give good advice.

I hope you come back and clarify! Welcome!

If you receive a distribution from a 401(k) ( I assume that's what you're asking about) that is subject to withholding, you should have received a notice notifying you of the opportunity to directly roll over the distribution to an IRA or another employer plan. If you take the distribution instead of doing a direct rollover, and you later want to roll it over, you can't get the tax withholding back. You can roll over the original amount, but you have to put in your own money to make up the amount that was withheld.

If the plan failed to provide the advance notice of your rollover rights, you may be able to challenge the withholding, but even in that case you won't get the withheld money back. The best you could do I think is send the check back and ask for a direct rollover election form.

I don't think you can roll over distributions not from a Roth account into a Roth IRA. Not positive on that point, though.

If I recall correctly, you should be able to do a custodian to custodian transfer without the withholding. If I asked for a check in my name they withheld 20 percent automatically and I would have had to come up with the difference to avoid it being a taxable distribution. Then I would have to wait to get the withholding back as a tax refund. This was for 401k to traditional IRA.

Remember anything you move from traditional 401k to Roth IRA is taxable income so you may owe MORE than is automatically withheld.