sims 4

can someone please help me with why when i go to cas and save the sim, or add sims to a lot from my library i am told than it cannot save and "the game is currently in a state where saving isn't possible.". i downloaded sims and origin yesterday so i'm assuming the version of the game is new - i'm playing on version 1.89.214.1230 on a macbook air, but i just can't work out why i'm unable to save and what's wrong with my game mode? when i go to library to place a lot it says "cannot place lot in this game mode", and on the options menu the save, save as, achievements and manage worlds options are greyed out. i have tried repairing the game on origin but that did not help.