Cannot submit tax return because it says Social Security number is being used for another file

[Bsch4477]

Mail your return with an explanation that your efile was rejected because your social security number was already used. Monitor your credit cards And financial accounts for possible identity theft. 

[tygrtchr]

There are a couple of possibilities here.  1) A parent or other family member has claimed you as a dependent; or 2) you are a victim of identity theft and the thief already filed his/her claim under your SSN.  It might take an in-person visit to your lRS office to get it straightened out

I would ask friends and family if they claimed you as a dependent and go from there.  Good luck.  The IRS will eventually get your refund to you if you were an ID theft victim.