Is there any reason an employer can with hold or refuse to give your your W2 form? Like if you owe them money, or have some of their personal property, etc.?
Legally they cannot withhold your W-2 based on other disputes. If your W-2 is being withheld, request it in writing with a deadline, referencing the date your accountant advises it was due. There is no legal claim really that an employee may have, but the tax regulations require that it be provided.