Grammar
Style guide 
disorganised and unorganised
Dis- as a prefix often implies the reversing of the action of the verb (e.g. disagree, disown, distrust).
Un- as a prefix means 'not' (e.g. unable, unusual, untidy).
Disorganised means thrown into confusion or disorder and unorganised means not organised.
The result is often the same: a mess.
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