Symptoms:

List what you or the client sees/experience that is not part of expected operation (e.g. attempting to start VM using web panel fails with "ERROR MESSAGE")

Cause:

Sometimes VMs fail to start or stop due to existing failed "prlctl start" process stuck in memory.

Resolution:

According our manual these are steps needed to stop  "prlctl start" process shown with examples taken from our manual:

1. Find out your Virtual Machine's UUID:
   [root@node ~]# prlctl list test.vm.com (http://test.vm.com/) UUID STATUS IP_ADDR NAME {08cd9db0-425a-649e-955c-5deec2e2c418} starting 192.168.55.1 test.vm.com (http://test.vm.com/)
2. Determine what prl_vm_app process is related to your Virtual Machine UUID:
   [root@node ~]# ps aux | grep 08cd9db0-425a-649e-955c-5deec2e2c418 | grep -v grep root 29960 0.0 0.0 134858224 16232 ? Sl 22:50 0:00 /usr/lib64/parallels-server/prl_vm_app {08cd9db0-425a-649e-955c-5deec2e2c418} {095c703b-a672-42e8-9b57-2722abd58b3b} ps
3. Kill the process to release Virtual Machine:
   [root@node ~]# kill -9 29960
4. Get rid of "prlctl start" processes which are starting your Virtual Machine, if any:
   [root@node ~]# ps aux | grep start | grep -v grep root 1941 0.0 0.0 108660 1216 ? S 20:37 0:00 /bin/bash /etc/rc3.d/S55parallels-server start root 29893 0.0 0.0 474484 14624 pts/1 Sl+ 22:50 0:00 /usr/lib64/parallels-server/prlctl start test.vm1.com (http://test.vm1.com/)
   If there are any prlctl start processes related to VM in question, kill them:
   [root@node ~]# kill -9 29893