If I start a virtual machine parallel 12 made every time a upgrade of the virtual machine. Why every time when I start the machine?
No, not the auto Update von Windows. It is not the Windows-Update. It is a Update from Parallels from the virtual machine.
Which build of parallels desktop are your running? If version 12.1.3 you can easily turn off windows updates from you parallels configuration menu. Go to Options< Maintenance < Check Start Maintenance and set a time and day. This will Block all updates until the specified time. If you are not using Parallels Desktop 12 you can just go into your windows 10 Vm and click the start menu and type "windows update settings" hit return or click the icon that comes up. when the window opens click advanced options and change "Automatic" to "Notify Me" and check the defer upgrades box. This will manually turn off the windows updates. After these changes restart the machine.