DIAGNOSIS Getting a "burn" message during the Sauté function is different from the pressure cook cycle. It means the sensor on the bottom of the inner pot is detecting an unsafe temperature spike, often because the pot is either completely dry or has too little oil/fat.
FIX 1) Immediately hit "cancel" to turn off the heat. 2) Let the pot cool down for a few minutes. 3) Add a sufficient amount of cooking oil, butter, or broth—at least a tablespoon or two for most sautéing jobs. The food or aromatics need a medium to conduct the heat. 4) Also, make sure you're using the correct Sauté setting. "More" is for searing/browning, "Normal" is for typical sautéing, and "Less" is for gentle warming. If you're starting with onions or garlic, use "Normal" or "Less" to avoid scorching before you add other liquids.
IF THAT DIDN'T WORK Check that the inner pot is seated flat on the heating element. If it's warped or has a concave bottom (unlikely but possible), it won't make good contact and can create hot spots. Also, ensure you're using the original stainless steel inner pot that came with the Ultra; third-party pots might not have the same conductive properties.
HEADS UP The Sauté function runs hot and fast, much like a stovetop burner. You need to keep an eye on it and stir frequently. It's not a "set and forget" mode. Never leave it unattended on Sauté.