How do I close the mkssandbox.log
What do you mean by "close"? Stop it being created or written to? What are you trying to achieve and why?
Stop it being created mkssandbox.log
This thread suggests that you cannot do that: https://communities.vmware.com/t5/VMware-Workstation-Pro/VMWare-Workstation-16-mksSandbox-log/m-p/22...
Why would you want to?
The default is none, but mkssandbox.log will be created.
Reselect the default, it will not be created after selecting none.
Correct. Why do you NOT want that file?