VMwareToolsUpgrader.exe has initiated the restart

Hi,

    One of the vm has rebooted in my environment.when i check the event logs of the VM it shows "The process C:\Windows\TEMP\vmware-SYSTEM\VMwareToolsUpgrader.exe (pord-vm1) has initiated the restart of computer pord-vm1on behalf of user NT AUTHORITY\SYSTEM for the following reason: Legacy API shutdown

Can any please let me know why the vm reboots?

Thanks in advance.