so this is a little advice, USE TIME MACHINE!!! i bought a new internal HDD and i use my old one a an external, to back up with time machine, anyways everytime i turned on my macbook i got a systemUI error message soooo i went into time machine and went back a couple days, found the folder that the bad file was in and i restored the entire file now it is working perfectly. so use time machine it is very useful. 






