This article is about how to upgrade your Virtualbox virtual machine to Windows 10. The thing is if you just start your VM and begin upgrading you may encounter some errors making the update process stop. Besides that Windows 10 can run too slowly if you leave CPU and RAM settings that are minimal for Windows 7.
Steps To Upgrade VM To Windows 10
- Turn off the virtual machine.
- Go to its Settings:
- Change Operating System to Windows 10 64-bit:
If you don’t and leave Windows 7, you will get the error related to not supported CPU during the upgrade: 
- Add some RAM and CPU cores to your machine:
- Click OK to save settings.
- Start the virtual machine:
- Now you can start upgrading your Windows to Windows 10. For instance, you can download and run Windows 10 Upgrade Assistant follow the steps:
If you don’t and leave Windows 7, you will get the error related to not supported CPU during the upgrade: 
Share your experience in the comments section.