diff --git a/platformio/commands/run.py b/platformio/commands/run.py
index f5f00670..cf6f7ae7 100644
--- a/platformio/commands/run.py
+++ b/platformio/commands/run.py
@@ -77,7 +77,7 @@ def cli(ctx, environment, target, upload_port, project_dir, silent, verbose,
                 config.get("platformio", "env_default"))
 
         check_project_defopts(config)
-        check_project_envs(config, environment or env_default)
+        check_project_envs(config, environment or env_default or [])
 
         results = []
         start_time = time()