All apps do this including ones deployed earlier (monday) this week (pre updates)
semaphore.h:90:8 [opt]
frame #8: 0x00000001101ad54a mlaunchfinalizer_thread at mono-coop-semaphore.h:43 [opt] frame #9: 0x00000001101ad53e mlaunchfinalizer_thread(unused=) at gc.c:903 [opt]
frame #10: 0x00000001102674f9 mlaunchstart_wrapper_internal(start_info=<unavailable>, stack_ptr=<unavailable>) at threads.c:1098:3 [opt] frame #11: 0x0000000110267357 mlaunchstart_wrapper(data=0x00007fd94b43ec60) at threads.c:1158:8 [opt]
frame #12: 0x00007fff5bb212eb libsystem_pthread.dylib_pthread_body + 126 frame #13: 0x00007fff5bb24249 libsystem_pthread.dylib_pthread_start + 66
frame #14: 0x00007fff5bb2040d libsystem_pthread.dylib`thread_start + 13

(lldb) detach

Got a SIGABRT while executing native code. This usually indicates
used by your application.

a fatal error in the mono runtime or one of the native libraries

(lldb) quit
Process 2472 detached
Would really appreciate some help, I'm loosing so much time over this and beginning to feel Xamarin is really not worth the pain
Rebooted all several times, tried several apps that were working fine before (no changes in code)