While trying to create a new clone / slave, instead of the vm being cloned, the following error is being thrown:

Provisioned agent MacOS10.10Slave-1 failed to launch
org.jenkinsci.plugins.vsphere.tools.VSphereException: java.lang.IllegalArgumentException: folder must not be null.
at org.jenkinsci.plugins.vsphere.tools.VSphere.cloneOrDeployVm(VSphere.java:169)
at org.jenkinsci.plugins.vsphere.tools.VSphere.cloneVm(VSphere.java:129)
at org.jenkinsci.plugins.vSphereCloudSlaveTemplate.provision(vSphereCloudSlaveTemplate.java:250)
at org.jenkinsci.plugins.vSphereCloud$1.call(vSphereCloud.java:274)
at org.jenkinsci.plugins.vSphereCloud$1.call(vSphereCloud.java:272)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: folder must not be null.
at com.vmware.vim25.mo.VirtualMachine.cloneVM_Task(VirtualMachine.java:164)
at org.jenkinsci.plugins.vsphere.tools.VSphere.cloneOrDeployVm(VSphere.java:158)
... 9 more

I tracked down in the source where this was happening, and it looks like this line is the problem:

Task task = sourceVm.cloneVM_Task((Folder) sourceVm.getParent(),
cloneName, cloneSpec);

So – "(Folder) sourceVm.getParent()" is returning null, and then the cloneVM_Task() function is checking that the folder is not null, and throwing this error.

I am not sure under what circumstances .getParent() on the source VM is allowed to be null – other clones of this same vm by the same ID, under similar api restraints is working fine – its only failing in our Jenkins instance with the above stack trace.