I recently attempted to roll over my 401K account from Mass Mutual to Vanguard. I was only 60% vested in the employer contribution portion of my 401K. Mass Mutual correctly withheld 40% of the employer contributions and they remained in my account. Mass Mutual then proceeded to take 40% of my 60% and called it a Forfeiture on the disbursement information. I have called them repeatedly and am still waiting for them to rectify the problem. They currently are saying they are researching it! If anyone else is in this situation you should double check their math.