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It is structured incorrectly.
Can you tell us in plain English exactly what you want it to do?
[COLOR=#333333]=IF(isblank(D12),[/COLOR][COLOR=#ff0000][B]IF[/B][/COLOR][COLOR=#333333](F17<365,F27,IF(F17>364,F37,f12)))[/COLOR]
=if(f17>365,f32,"")please let us know your values in the following cells, so we can try to recreate your scenario:
d12f12 =if(and(isblank('start here'!c6),isblank('start here'!c7),isblank('start here'!c8),isblank('start here'!c9)),"",d12)
7/2/2018
<tbody>
</tbody>f17
<tbody>
</tbody>
=datedif(d11,d12,"d")
f27
=if(f17<365,f22,"")
f37