Individuals who are naturally unattuned do not possess an innate attunement to the magical fields of Fillimet. They are still able to cast magic with the aid of a Focus and the appropriate magical training.
If a naturally unattuned individual wishes to cast their own magic they must identify a Focus through which they will channel their magical intentions. The focus must have strong sentimental value to the caster and does not require any magical properties on its own. It is merely a tool to help the caster ground themselves so they can attune to the magical fields required to cast their desired spell.
Among sapient species who are Naturally Attuned it is considered especially bad luck for an individual to be born Unattuned, and some magical groups also look down on those from any species who are not naturally gifted with access to the magical fields. For most species however, being naturally unattuned to the magical fields is a standard fact of life. As a result Unattuned individuals are not treated differently by society as a whole, especially since the use of a Focus allows them to temporarily attune to the fields and cast magic anyway.