Hi guys I am a Pro Mac user, and have been looking for a solution to a big problem with my Mac all day, and didn't find any solution. I really hope someone here can give me a valuable hint to solve my problem... MacBook Pro, late 2013 The problem suddenly appeared yesterday. I was booting up a Parallels VM, when suddenly my Mac freezes completely: no more mouse movement. I did a hard reset, and tried again. Again: total system freeze. I thought it was a Parallels problem, so I reinstalled Parallels, but the problem persisted. Then, I noticed it was no Parallels problem, but a wider problem: many other third-party apps also caused my Mac to freeze at startup of the app. For example, every Adobe app also freezes my Mac at startup of the app. Not all third party apps do this. For example, Microsoft Office works fine. And all first-party apps by Apple also work fine. I'm writing this post on my Mac. However, there is something seriously wrong. While trying to find a solution, I noticed other problems. Booting my Mac in normal mode succeeds without a problem, but when trying to boot my Mac into safe mode or into Recovery Mode, it just ends with a black screen, after showing the Apple logo and the progress bar for a short time. So I can't boot my Mac into Recovery Mode. I did a Disk Check, and everything seems to be fine, no errors found. Ultimately, I decided to do a complete reinstall, but that also fails. I tried to boot my Mac from a freshly made El Capitan install volume (on SD card), and this also strands me on a black screen. So I have _no idea_ what to do next. I can't keep using my Mac like this because half of my third party apps crash my Mac completely. But I'm unable to do a recovery, or to do a fresh reinstall of my OS. Any suggestions what might be wrong, and what I can do about it? Every suggestion is greatly appreciated... I'm kind of desperate. Thank you! Karel PS: I don't use Transmission or any other torrent client.