Have you tried running in an environment with Python 3.11? I’ve been stuck on version 1.7.3 of anvil-app-server for a long time (because of organizational requirements where it’s installed in existing projects), so I can’t speak about the most recent version, but that runs well in Windows 11. You do in some cases need to install MS C++ 2013 redistributable, as in the solution here: Anvil App Server; Failed to start built-in Postgres database - #4 by tomaz.turk