Minn. Stat. § 277.24: UNCOLLECTED TAXES.

If at any time in the collection proceedings the county treasurer is satisfied that the tax cannot be collected for any reason or finds that the collection costs are excessive in comparison to the amount of tax involved, the treasurer may cancel the taxes due. A list of canceled taxes must be kept by the treasurer for a period of six years. The list must identify the taxpayer, the amount of uncollectible liability, and the reason for uncollectibility.