I've seen this happen consistently on some (virtual) machines - clicking the stop button causes it to grey-out (but not enable start etc), but seem to wait forever in the "stopping" state without actually stopping. Unfortunately, I don't have a fix.
However, the systems where this happen were all fairly low-resource VPCs. The fact that this always happened for the VPCs, but never for my desktop system made me suspicious that it may be related to low memory availability, or else something about the VPC environment, but I never confirmed this for certain.
At the time, I worked around it by connecting remotely, running profiler on my own machine. If this is a low-spec machine / VPC, it may be worth trying this, or else closing all apps on the machine before using profiler.