Hello, I've been waiting so long for the problem(s) to be solved by APPLE, but still ..... (High)Sierra is bad at task switching: programs 'freeze' for some time, with or without the corresponding busy cursor or 'ball', until you fiddle with some other programs. Then suddenly it comes back to life again. I noticed that programs involved are: - all (!) macOS components, - third party programs (Mozilla stuff, VLC, LibreOffice, CrossOver, SuperDuper!, Vim ...), - my own applications written in JAVA-10. Furthermore: the 'hangs' seem to happen between members of above groups, which means that none of these programs can be proved to be the single cause. It certainly is an OS problem. Having worked in the past with 6- and 16-cpu systems that had similar problems, I suspect the thread-to-core run-time distribution part of the kernel. ;JOOP!