diff --git a/model_manager/worker/worker.py b/model_manager/worker/worker.py
index 8e94429..631e29d 100644
--- a/model_manager/worker/worker.py
+++ b/model_manager/worker/worker.py
@@ -79,8 +79,8 @@ def _get_runtime(runtime: str | None) -> str:
 
 def _loaded_distribution_versions() -> dict[str, str]:
     """Version on disk of every installed distribution whose top-level module is imported."""
-    # list() copies the keys: another thread importing while we iterate would raise RuntimeError.
-    loaded = {name.partition('.')[0] for name in list(sys.modules)}
+    # Iterate a copy: another thread importing while we iterate would raise RuntimeError.
+    loaded = {name.partition('.')[0] for name in sys.modules.copy()}
     return {
         dist: importlib.metadata.version(dist)
         for module, dists in importlib.metadata.packages_distributions().items()