fillet issues. Is it just me? =P

 From:  DannyT (DANTAS)
3917.2 In reply to 3917.1 
Nothing obvious Chris,

MoI hasn't got the strongest filleting engine out there so it does struggle to solve some fillets on occasions.

Your model could do with a little cleaning up, but on doing that the fillet still failed, so one work around would be to cut the model up using Boolean>Diff with a couple of lines as shown in the picture, apply the fillets then 'glue' everything back again with Boolean>Union.