Unable to register virtual machine

Products

• VMware vSphere ESXi
• VMware vSphere ESXi 8.0

Issue/Introduction

• When selecting the virtual machine <vm_name.vmx> file, the "REGISTER VM" option is greyed out.
• Even if the virtual machine is registered using command line, the virtual machine appears as invalid in inventory. 
• /var/run/log/hostd.log on ESXi host has below messages:
  
  DictionaryParseReadLine: syntax error with line, "<XXXXX> = <not printed>".
Unable to load configuration file '/vmfs/volumes/<datastore UUID>/<vm_name>/<vm_name.vmx>'.
File "/vmfs/volumes/<datastore UUID>/<vm_name>/<vm_name.vmx>" line <line number>: Syntax error.
  
  
• Issue usually occurs when there's problem with virtual machine configuration file <vm_name.vmx> and the file is rebuilt following Recreating a lost or deleted vmx file.

Cause

There are invalid options in virtual machine configuration file <vm_name.vmx>.

Resolution

The invalid line in virtual machine configuration file <vm_name.vmx> needs to be commented out: 

1. Connect to the ESXi host via ssh 
2. Locate the <vm_name.vmx> file and look for the line as mentioned in above logs with invalid values
3. Comment out the invalid line 

Another attempt to re-register virtual machine can be made after removing the invalid line to see if the virtual machine can be successfully registered and powered on.