Hi there, have made sure the modules you have active are made compatible with V13 Foundry?
Jump from v11 to v13 is no small thing so it’s likely the modules you’re used to haven’t been updated.
Also make sure that the game system itself has actually been updated to latest v13 update.
Try starting your world with Safe Configuration enabled and then check manually which modules are good to activate for v13.
Hi again, I’ve just checked and WFRP4e is updated for v13 as seen in the Bazaar.
It is possible it’s dependency didn’t download/update properly.
Things to try would be go to Bazaar and uninstall this game system and it’s dependency, then go to Forge setup page and select View Data Storage, if you see the game system there or it’s dependency remove them as well, then reinstall the game system via the Bazaar making sure it downloads the dependency again.