You must file a Utah individual income tax return if:
If you must file a Utah return, first complete a federal return, even if you're not otherwise required to file with the IRS. You need information from the completed federal return to complete the Utah return.
You may be exempt from Utah individual income tax if your federal adjusted gross income is less than the sum of your federal standard deduction and your federal personal exemptions for the taxable year. See Exemption from Utah Income Tax for more information.
Utah nonresidents whose only source of Utah income was from being a member of a pass-through entity (entities taxed as partnerships, S corporations, or trusts), are not required to file a Utah return if the pass-through entity withheld Utah taxes on the income. They may file if they would be due a refund of all or part of the taxes withheld. If taxes have not been withheld on the Utah sourced income passed through to you, you must file a Utah return.
If you are due a federal income tax refund from the IRS, you only have three years to file and claim it. The IRS has a short video, Haven't Filed a Tax Return in Years? and a publication, Haven't Filed a Tax Return in a While? that both give more information.
Statute of Limitations gives more information about Utah's statute of limitations for applying for a refund.