packer template for building a BIG-IP box

Tim,

I would like to thank you for the hard work you put in to produce this Vagrant box. I am noting issues with deploying it on a 12.x code release, but it looks to be an issue with Virtualbox rather than the image itself.

Any chance you could decipher the following error message?

2016/08/15 18:59:51 packer: 2016/08/15 18:59:51 Executing VBoxManage: []string{"controlvm", "BIGIP-12.1.0.0.0.1434.LTM_1SLOT-ide", "poweroff"}
2016/08/15 18:59:52 packer: 2016/08/15 18:59:52 stdout:
2016/08/15 18:59:52 packer: 2016/08/15 18:59:52 stderr: 0%...10%...20%...30%...40%...50%...60%...70%...80%...90%...100%
2016/08/15 18:59:52 ui: ==> virtualbox-ovf: Unregistering and deleting imported VM...
==> virtualbox-ovf: Unregistering and deleting imported VM...
2016/08/15 18:59:52 packer: 2016/08/15 18:59:52 Executing VBoxManage: []string{"unregistervm", "BIGIP-12.1.0.0.0.1434.LTM_1SLOT-ide", "--delete"}
2016/08/15 18:59:52 packer: 2016/08/15 18:59:52 stdout:
2016/08/15 18:59:52 packer: 2016/08/15 18:59:52 stderr: VBoxManage: error: Cannot unregister the machine 'BIGIP-12.1.0.0.0.1434.LTM_1SLOT-ide' while it is locked
2016/08/15 18:59:52 packer: VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component MachineWrap, interface IMachine, callee nsISupports
2016/08/15 18:59:52 packer: VBoxManage: error: Context: "Unregister(CleanupMode_DetachAllReturnHardDisksOnly, ComSafeArrayAsOutParam(aMedia))" at line 155 of file VBoxManageMisc.cpp
==> virtualbox-ovf: Error deleting VM: VBoxManage error: VBoxManage: error: Cannot unregister the machine 'BIGIP-12.1.0.0.0.1434.LTM_1SLOT-ide' while it is locked
==> virtualbox-ovf: VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component MachineWrap, interface IMachine, callee nsISupports
==> virtualbox-ovf: VBoxManage: error: Context: "Unregister(CleanupMode_DetachAllReturnHardDisksOnly, ComSafeArrayAsOutParam(aMedia))" at line 155 of file VBoxManageMisc.cpp
2016/08/15 18:59:52 ui error: ==> virtualbox-ovf: Error deleting VM: VBoxManage error: VBoxManage: error: Cannot unregister the machine 'BIGIP-12.1.0.0.0.1434.LTM_1SLOT-ide' while it is locked
==> virtualbox-ovf: VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component MachineWrap, interface IMachine, callee nsISupports
==> virtualbox-ovf: VBoxManage: error: Context: "Unregister(CleanupMode_DetachAllReturnHardDisksOnly, ComSafeArrayAsOutParam(aMedia))" at line 155 of file VBoxManageMisc.cpp
2016/08/15 18:59:52 ui: ==> virtualbox-ovf: Deleting output directory...
==> virtualbox-ovf: Deleting output directory...
2016/08/15 18:59:52 ui error: Build 'virtualbox-ovf' errored: Script exited with non-zero exit status: 1
2016/08/15 18:59:52 Builds completed. Waiting on interrupt barrier...
2016/08/15 18:59:52 machine readable: error-count []string{"1"}
2016/08/15 18:59:52 ui error: 
==> Some builds didn't complete successfully and had errors:
2016/08/15 18:59:52 machine readable: virtualbox-ovf,error []string{"Script exited with non-zero exit status: 1"}
2016/08/15 18:59:52 ui error: --> virtualbox-ovf: Script exited with non-zero exit status: 1
2016/08/15 18:59:52 ui: 
==> Builds finished but no artifacts were created.
2016/08/15 18:59:52 waiting for all plugin processes to complete...
2016/08/15 18:59:52 /usr/bin/packer: plugin process exited
2016/08/15 18:59:52 /usr/bin/packer: plugin process exited
Build 'virtualbox-ovf' errored: Script exited with non-zero exit status: 1

==> Some builds didn't complete successfully and had errors:
--> virtualbox-ovf: Script exited with non-zero exit status: 1

==> Builds finished but no artifacts were created.
2016/08/15 18:59:52 /usr/bin/packer: plugin process exited