Changing Windows 10 System Clock Doesn't Work

Solution 1:

Since you are using a VM with VirtualBox, your VM will automatically sync with the host computer. You will need to disable this time sync feature as written in the VirtualBox manual.

You can disable time sync by doing the following.

1. Find your VM's .vbox file on your host machine. (You can do this by right clicking the VM in the main VirtualBox window and selecting "Show in Explorer" or "Show in Finder".)
2. Shutdown your VM and confirm VirtualBox is no longer running.
3. Make a backup copy of this .vbox file.
4. Open the original .vbox file in a text editor.
5. Under the <ExtraData> tag put the following line: <ExtraDataItem name="VBoxInternal/Devices/VMMDev/0/Config/GetHostTimeDisabled" value="1"/>
6. Save the text file and close the text editor.
7. Start VirtualBox and your VM.

You should now be able to change your VM's date and time independently of your VM host machine. If you ever want to sync time with your host machine again, remove the line or set the value of this line to value="0"