diff --git a/PC/_subprocess.c b/PC/_subprocess.c
index f107c13..a09b016 100644
--- a/PC/_subprocess.c
+++ b/PC/_subprocess.c
@@ -385,6 +385,9 @@
 	si.hStdOutput = gethandle(startup_info, "hStdOutput");
 	si.hStdError = gethandle(startup_info, "hStdError");
 
+	if (PyErr_Occurred())
+		return NULL;
+
 	if (env_mapping == Py_None)
 		environment = NULL;
 	else {