Light Building Stuck at 99%

Hi. So I decided to build some of that Light for ma level. But you know what? I got mothercreeping stuck! Stuck at 99% and wont move! For hours! What’ts wrong? I mean dont just ignore this message just because I am

black, I kinda have a serious issuse and I am not able to build the lighting! Please help!

hmm, how big is your scene ? how big are the resolutions of your lightmaps ?
Maybe you have to less main memory to calculate your scene.