My mother died, but prepared a Quit Claim Deed transferring home to kids. Filing it now should avoid probate in WI, correct?

Even if the deed was not recorded during your mother's lifetime, the transfer was complete upon her signing it. Yes, you can record it now and the asset will not be subject to probate. If her other assets were under $50,000 you can use an Affidavit instead of starting a probate. The transfer of the house is exempt from the Wisconsin Transfer Tax because it is a gift to her children. If the deed reserved a life estate for your mother (which means it would pass free of any capital gain taxes) then you have to file an HT-110 form with the county Registrar of Deeds office. If there was no life estate reserved in the deed you don't need to do anything but record the deed, and pay any capital gains taxes upon sale of the house.

Technically, the deed had to be delivered to the grantee before her death. I doubt anyone will ask, though.

Hello, I attached a link from the WI Bar Association that explains probate. If you have any further questions you should consult with a local probate attorney.