"Household inventory is not available in free build mode" [SOLVED]

Hi everyone! 

I am new here so I hope my issue is not going to seem dumb to you >.<

My Sim was just rewarded with an object placed in the family inventory. Problem is, when I try to access it, I get this message: "Household inventory is not available in free build mode".

Is this a bug or is this just me being dummy and looking for the inventory in the wrong place (you will have guessed I tried accessing it from the "Build" menu)?

Have a good day everyone! =)

//EDIT


The bug disappeared after I saved the game. It happens again sometimes but if I save again it goes away.


Helper edit: Thanks for letting us know. Problem solved, topic closed. 
- SeoY