The work income of a non-resident of New York who never physically works within New York during the tax year, not even for a single day, is not subject to New York income tax.
The convenience rule applies only to employees who physically work both within and without New York during the tax year. See the first paragraph of the New York tax memorandum that I cited in my earlier reply.
If New York income tax is incorrectly withheld, the taxpayer's remedy is to submit a non-resident NY tax return, showing the withholding but claiming zero New York income.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
