Material UI Select Component- A component is changing a controlled input of type text to be uncontrolled

Uncontrolled here means you may be setting the value of the Select component to undefined, this is because value={props.selectedValue} here. In this the props or selectedValue may come null so it turns out to be a uncontrolled component in that.

To solve the warning you can add condition to check null and set default value.

value={props.selectedValue ? props.selectedValue : " "}

the same of the accepted answer but check for undefined and provide default value with nullish coalescing operator (??)

value={props.selectedValue ?? ""}