Follow the requested information

- did you made an in-place-upgrade or a clean install + data transfer
I made in-place-upgrade
- the class in question is the same on IRIS and Cache (i.e. no change was made)
Yes, is this same on IRIS and Cache, no change was made
- is the class re-compiled (on IRIS)
Yes, re-compilde on IRIS
- what do you exactly mean when you say "Not opening an instance...": (1) you get an NULL-OREF or (2) you get an error
I get an NULL-OREF
- what do you provide as a NULL value: (1) "", (2) $c(0), (3) " " or something else as open parameter
""A shortened

"" String Empty

Shortened class:

Class dado.TblTeste Extends (%Persistent, dado.Persistente)

Index idxFieldOneFieldTwoFieldThree On (FieldOneId, FieldTwoId, FieldThreeId) [ Unique ];

ForeignKey fkFieldOneId(FieldOneId) References dado.TblFieldOne();

ForeignKey fkFieldTwoId(FieldTwoId) References dado.TblFieldTwo();

ForeignKey fkFieldThreeId(FieldThreeId) References dado.TblFieldThree();

Property FieldOneId As dado.TblFieldOne [ Required ];

Property FieldTwoId As dado.TblFieldTwo [ Required ];

Property FieldThreeId As dado.TblFieldThree;

Property Descricao As %String [ Required ];

Property VersaoCheck As %String [ InitialExpression = 0 ];



Set object = ##class(dado.TblTeste).idxFieldOneFieldTwoFieldThreeOpen(1, 2, "")