In this video I start out with a virtual Windows Vista PC and upgraded it to Windows 11 via Windows 8, Windows 8.1 and Windows 10.
With Windows 11 being 64bit only and wanting to do only in place upgrades this meant I had to start out with a 64bit OS. Microsoft released a 64bit version of Windows XP but that wasn’t upgradable, so I had to start with Windows Vista (x64).
Then it was a case of install Vista SP1 and then an upgrade to Windows 8, Windows 8.1 followed by Windows 10. For virtualisation I am using Microsoft Hyper-V and Vista only works on Generation 1 virtual machines whereas Windows 11 only works with Generation 2 machines.
There is no upgrade path from Gen 1 to Gen 2 so converted the disk layout to GPT using the command:
mbr2gpt.exe /convert /allowFullOS
Then I created a new Gen 2 virtual machine and mounted the existing hard drive, once I enabled TPM 2.0 and secure boot I installed Windows 11.
So, there you go, Windows Vista to Windows 11 with in place upgrade and no loss of any files or performing a clean install. This was all just for the sake of doing it rather than a real-world example, but it shows it is possible!