Box 12 W on W-2

code 12w on a w-2 is only for HSA contributions. if the employer either directly or thru a salary reduction program has been contributing to an HSA where's the money?  if you don't have an HDHP, you don't qualify to have an HSA. only your employer can tell you what's going on. it may need to issue a corrected w-2 ie w-2c.  you can't file if the w-2 is wrong. your 1040 is due tomorrow so you'll either need to extend it or mail in an incorrect 1040 (without 8889 you won't be able to e-file). any taxes due must be paid by 5/17/2021. after that you will have penalties and interest for late payment.