This morning I received the following error when trying to power on a VMware Workstation virtual machine:

Could not open virtual machine: C:\VMs\Windows Server 2003 Standard Edition.vmx. This virtual machine appears to be in use.

To resolve the issue, I deleted all of the .lck files and directories in the guest’s directory listed above. This allowed me to start my VM. I encounter this error from time to time, yet always forget how to resolve it.