VM in virtualbox is already locked for a session (or being unlocked)
VirtualboxVirtualbox Problem Overview
My VM in virtualbox can not start due to this error, I don't want to destroy it and reinstall it again, anyway to recover it ?
There was an error while executing VBoxManage, a CLI used by Vagrant
for controlling VirtualBox. The command and stderr is shown below.
Command: ["modifyvm", "319fcce3-e8ff-4b6f-a641-3aee1df6543f", "--natpf1", "delete", "ssh"]
Stderr: VBoxManage: error: The machine 'centos64_c6402_1454036461345_59755' is already locked for a session (or being unlocked)
VBoxManage: error: Details: code VBOX_E_INVALID_OBJECT_STATE (0x80bb0007), component MachineWrap, interface IMachine, callee nsISupports
VBoxManage: error: Context: "LockMachine(a->session, LockType_Write)" at line 493 of file VBoxManageModifyVM.cpp
Virtualbox Solutions
Solution 1 - Virtualbox
Running this on the command line unlocked the VM:
vboxmanage startvm <vm-uuid> --type emergencystop
Where <vm-uuid> is the number in the error message: Command: ["modifyvm", "<vm-uuid>" [...]. After that I was able to control the VM (start, halt, etc).
Using Virtualbox 4.1 on Ubuntu.
Solution 2 - Virtualbox
Having the same issue I found that there was a process running actually locking the vm:
501 79419 79323 0 2:18PM ?? 0:39.75 /Applications/VirtualBox.app/Contents/MacOS/VBoxHeadless --comment default --startvm 1d438a2e-68d7-4ba2-bef9-4ea162913c1b --vrde config
Make sure you don't have a process stuck trying to start the vm:
ps -ef | grep -i "vbox"
Solution 3 - Virtualbox
I found this answer from @Gonzalez very interesting.
vboxmanage startvm <vm-uuid> --type emergencystop
The only problem with that it shut down the current instance of my VM, so instead of using modifyvm you can use controlvm if the current vm is running.
For example:
VBoxManage modifyvm <vm_name> --natpf1 "guestssh,tcp,,22,,2222"
VBoxManage modifyvm <vm_name> --natpf1 delete "guestssh"
Become:
VBoxManage controlvm <vm_name> natpf1 "guestssh,tcp,,22,,2222"
VBoxManage controlvm <vm_name> natpf1 delete "guestssh"
Full documentation Here https://www.virtualbox.org/manual/ch08.html#vboxmanage-controlvm
Solution 4 - Virtualbox
For me I had to kill the VboxHeadless.exe process in task manager. I also had to ensure CMD prompt was opened in Administrative mode.
Solution 5 - Virtualbox
sudo pkill -9 VBox kills everything running related to vbox
Solution 6 - Virtualbox
In Windows Task Manager, I ended any tasks related to Virtual Box (you can see they start with a V in Task Manager like Vbox Headless.exe, etc). Once I did that, I was able to get this error to go away (the above 'vboxmanage startvm
Solution 7 - Virtualbox
If you have a settings window open for that box in the VirtualBox GUI, you may run into this error. Just close the settings window and try again.
Solution 8 - Virtualbox
I've encounter the same error message today:
>me@myhost:~$ ps -ef | grep -i "vbox"
me 3064 1 0 08:51 ? 00:00:00 /usr/lib/virtualbox/VBoxXPCOMIPCD
me 3089 1 0 08:51 ? 00:00:00 /usr/lib/virtualbox/VBoxSVC --auto-shutdown
me 3126 3089 27 08:51 ? 00:00:39 /usr/lib/virtualbox/VBoxHeadless --comment RHEL5 64-bit desktop --startvm e5c598d8-1234-4003-a7c1-b9d8af15dfe7 --vrde config
me 3861 3415 0 08:53 pts/1 00:00:00 grep --color=auto -i vbox*
Gergely's answer solves it perfectly. It turned out that I've a crontab set at reboot to boot the virtual machine, which initiated the three VBox process shown above
me@myhost:~$ crontab -l
@reboot me /usr/bin/vboxmanage startvm "RHEL5 64-bit desktop" --type headless
Solution 9 - Virtualbox
The only option that worked for me was to kill all the processes matching ps axl|grep -i vbox.
Solution 10 - Virtualbox
In my case, the apparent cause was a USB ethernet adapter that had been removed after suspending the machine. In my case,
vboxmanage startvm <vm-uuid> --type emergencystop
did not help. Instead, I received the confusing message that
> VBoxManage: error: The machine 'xyzzy' is not locked by a session
The true error was revealed by running
vboxmanage startvm <vm-uuid> --type gui
which returned
> VBoxManage: error: Nonexistent host networking interface, name 'en9: USBPlug' (VERR_INTERNAL_ERROR)
Changing the network configuration to a different network adapter solved the issue.
Solution 11 - Virtualbox
This is because You reallocated the memory set for Virtual Box
What you have to do to fix is: Restart The PC