I used Vcenter standalone converter 6.5 on a VMware workstation machine.
After approximately 5 hours of operations at last some error happened probably the USB plug in which virtual machine was being generated became loose.
Screenshot below.
I again next day tried to create a virtual machine from the physical machine but operation this time had permissions error.
As in screenshot below.
I am trying to create virtual machine approximately 500Gb of a laptop which is powered on and is having 1TB hard disk.
Did you start the Converter in elevated mode, i.e. using "Run as Administrator" from the pop-up menu?
André