When adding a 1-wire device, a port and pin of a U4x1 device must be selected. The pin is then reserved for the 1-Wire device and is not available for direct control. If you try to change the properties of a pin that is reserved for a 1-Wire device, this warning message will appear. The Item Name is the name of the pin, and the message contains the name of 1-Wire device that uses this pin.
If you need to make this pin available for direct control, you will need to change the 1-Wire device to use a different pin, or delete the 1-Wire device.