As of Arnold 18.104.22.168, the minimum Windows version is Windows 7. We no longer support Windows versions before Windows 7 and Windows Server 2008 R2.
If you try to load an Arnold plugin on an unsupported Windows, you’ll get an error (something like “The specified procedure could not be found”).
On Vista with Arnold 22.214.171.124 or later, kick -nodes gives you a more specific error:
"kick.exe - Entry Point Not Found" "The procedure entry point SetThreadGroupAffinity could not be located in the dynamic link library KERNEL32.dll."