Why is matlab always stuck in busy state?

Recently i have a problem with matlab that whenever my code contains of even simple loops then it is stuck during execution in busy state so i can not go any further. I use matlab 2015a on Dell XPS with ubuntu 16.04 Lts. I am also a beginner to matlab but i have never had that kind of problem before even with looping over large matrices. Any help would be appreciated.

[Geoff Hayes]

Ice - is this is a problem with all loop or just certain ones? Please provide an example that exhibits this behaviour.

[Image Analyst]

Is it a for loop or a while loop? It would not be that common with a for loop, but happens frequently with while loops because beginners don't know to put in a failsafe and thus get infinite loops. We'd have to see the code in order to fix it.