My ProBoolean objects disappear from the scene and from the list after hidding.

[Anonymous]

So, here's my issue:
I'm making my house (I'm a student) for homework. When I Made the window and door spaces with pro-booleans there was no problem at all, until I hid the second floor. After that, the whole second floor (even the walls made with primitive objects (non-proboolean) disappeared. They are not listed on the list, neither are shown (or any vestige of) on the scene. Is this a bug? There was no external factor that may have erased my things, as I was alone, working for hours non stop. I did not clicked by accident the Del key, as for I tested a new pro-boolean, hide it, made another pro-boolean and the first was gone from existence.
Thank you for your time!!

[irishman_team_kilber]

I usually made the ground floor first add everything you need for that ground floor including the booleans then group it together, name it ground floor and add the ground floor to the layer manager,name it the same in the layer manager

Then clone the ground floor as a copy, name it first floor and then move it up above the ground floor, name this first floor, then add the first floor to the layer manager, then hide the ground floor or even freeze the ground floor.

i never convert it down because you lose the option of max cutting a hole in the wall so you can place the windows and door.

[irishman_team_kilber]

if you lose the Boolean tool and you cut a box into the wall, then turn edgesfaces on then see max makes a complete mess on the walls lines going through the walls. once you turn it edge face off you won't see the lines. but i don't like use the proBoolean or Boolean tool.

you can always use the cut tool or the quick slice to get a better result,