LG lists UE on its top-load washers under unbalance error. The washer reached spin, sensed the drum was swinging beyond what its suspension allows, and stopped rather than let a wet, heavy load hammer the cabinet. That is protective behaviour, and the machine is telling you something about the load, the installation or occasionally the sensor.
uE Versus UE
The display distinguishes two states. Lower-case uE means the washer has detected imbalance and is trying to correct it: it adds water, tumbles the load to redistribute it and attempts spin again, which is why a cycle can run far longer than its estimate. Upper-case UE means those attempts have been exhausted and the cycle has stopped waiting for you. If you see uE, let the machine work. If you see UE, open the lid and look at how the load is lying.
The Load Is the Usual Cause
One heavy wet item on its own, a bath mat, a pair of jeans, a single towel, cannot balance itself in a drum and will drift to one side at every spin. Add two or three similar items so the weight spreads. Very large loads have the opposite problem: they pack so tight that they cannot move to redistribute. Waterproof and water-resistant items, such as mattress covers, rain jackets and outdoor cushions, are a special case, and LG's manuals say not to wash them in a top-loader: they trap water, form a heavy pocket and cause an imbalance strong enough to damage the machine. Bulky bedding wants the cycle designed for it.
Then the Feet
A washer that is not sitting flat on all four feet will report imbalance with a perfect load, because the cabinet rocks before the drum does. Put a hand on each top corner and press down in turn; any rock means a foot is short. With the washer unplugged and the tub empty, adjust the feet according to your model's installation instructions. Some LG top-loaders have adjustable feet at all four corners with lock nuts; others have self-levelling rear feet that set themselves when the front of the machine is tipped a few degrees forward and lowered again. A full washer is far too heavy to tilt safely, so this is done empty, and if the machine sits on a pedestal or a soft floor, the surface underneath is part of the answer.
vS and uS: the Vibration Sensor
Some LG top-loaders carry a vibration sensor and show vS or uS when it reports excessive movement. It behaves like UE from the owner's point of view, and the same load and levelling checks apply first. A sensor that trips on every cycle with a balanced load and a level machine is a sensor or wiring fault to be looked at rather than lived with.
When It Is Not the Load
If a small, mixed load of towels on a level machine still ends in UE, the suspension rods that hang the tub inside the cabinet may have lost their damping, or the sensor may be misreading. Both are internal, both involve removing the cabinet top or panels with the washer disconnected from power and water, and neither is an owner task. Note whether the drum feels loose when you push it side to side with the machine off, whether the cabinet bangs during spin, and whether the fault started suddenly or crept in, then book an LG washer repair with the model number from the plate under the lid.