My Mac suddenly come up a strange issue when using fast user switching about 2 weeks ago. There are 2 profiles in my Mac. If I login Profile A first, when I switch to Profile B, the wallpaper cannot be correctly display during switch. After the animation completed, the wall paper will back to normal. However, all windows will be automatically resized and move to the top left corner as the following attachment shows. The interesting thing is if I login profile B first, then profile A will suffer the same problem (but profile B will be completely normal). If I then further logout and login Profile B, then both Profile will suffer the same issue. Did anyone experience this before? Any way to fix it? I hope the 10.9.3 upgrade will fix it automatically but it is not. Or any testes I can do to find the real problem? Million thanks in advance.