My w-2 does not have a Utah state ID number for my employer because I work remotely for a company in a different state. It will not let me file without it. Any ideas?

[SteamTrain]

IF they didn't withhold any UT taxes...then try leaving boxes 15,16,17 entirely blank for the UT state line.

[TeresaM]

If box 15, State Employer ID, is blank on your W-2, your e-file return should still go through just fine, as long as there are no other errors on your return.  Your state department of revenue will be able to easily identify your employer from their 9-digit federal EIN, so the state ID number is a little redundant anyway, but is still a way that your state tracks employers in their internal state computer system. 

SteamTrain is quite right, if there are no entries in 17, you may leave the entire box 15 and 16 blank, as well.  If you do have entries in box 17, please see the work around below.
 

If you are receiving an error for box 15, try using the federal ID in that box or if the state requires a particular format, such as ending in wth, then enter 99999999wth for the number of digits it specifies. In Utah, there should be 11 numerals followed by wth (in lower case with no dash)