Box 14 has multiple entry's but the system says it is a duplicate entry however that is how it is listed. It only gives me the option to file by mail now. how to fix?

I assume the TurboTax program is telling you that the information in Box 14 of your W-2 is duplicated ELSEWERE, in the program, either from another box on your W-2 or from some other form you entered. 

Box 14 on a W-2 can be used for many different items, usually items that only your payroll department is interested in. 

From time-to-time Box 14 does hold relevant information for your state tax return. 

If the TurboTax program has picked up the same information twice, try deleting the entries from Box 14 (leave them blank). 

If the error message stops, and your refund (or tax liability) stays the same, Box 14 on the W-2 can be left blank. 

If you are unsure what is being reported in Box 14, ask your payroll department what is being reported there and if it needs to be reported. 

Here is a link with more information.