I just noticed that there has been a major upgrade to mbed 5.1. That seemed to have broken some of my code where I was using rtos in combination with sleep function.
In fact I just tried to load Sleep Example program, which works on the old libraries, but as soon as I update the libmdot and/or rtos libraries it fails.
It would be really nice if the example code was updated to the latest binaries as it seems quite outdated.
See here screenshot from the errors.