Sub ReloadCertPlanOwner() is only used to reload Uf_CertPlan_Owner (not Uf_AirplaneCertSubCat). However I have other modules that do the same thing (with minor tweaks) for other userforms. Currently the code is setting the 3 listboxes while the userform has not yet been shown (it is not in hide, it has not yet been lauched). Do you think that is the problem? But how do I set the 3 listboxes once the userform is shown? Am I not correct to say that code exicution stops once you issue Uf_AirplaneCertSubCat.show?

Ok I just changed the code to launch Uf_CertPlan_Owner.SHOW prior to setting the 3 listboxes, code exicution does stops and the userform appears incomplete (because code exicution stopped prematurely).

I just changed the code to launch Uf_CertPlan_Owner.HIDE prior to setting the 3 listboxes, code exicution does not stops and the SowMaturity listbox does not set (the other two listboxes set ok).