After aborting the master kernel during a parallel computation and if remote kernels do not respond, you can try to reset them and bring them back into a usable state.

ResetSlaves can be used after a parallel computation has been aborted with the menu command Kernel Abort Evaluation, or ..

For some remote kernel connections, notably for kernels started on remote machines using LinkLaunch, there may be no way to interrupt them. If a remote evaluation takes too long or is in an infinite loop, you must terminate the remote kernel process using the appropriate operating system command.