diff --git a/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc b/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc
index 119f99e..6235051 100644
--- a/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc
+++ b/core/wasm_shims/pythonplugin/python_plugin_probe_main.cc
@@ -1,5 +1,6 @@
 #include "pythonplugin/python_plugin.hh"
 
+#include <cstdlib>
 #include <cstdio>
 
 // LinuxCNC source basis: src/emc/pythonplugin/python_plugin.cc and
@@ -28,6 +29,10 @@ int main() {
     if (plugin->run_string("noop", retval, false) != PLUGIN_OK) {
         return 3;
     }
+    unsetenv("INI_FILE_NAME");
+    if (plugin->configure(nullptr, "PYTHON") != PLUGIN_NO_INIFILE) {
+        return 21;
+    }
     const char *ini = "/tmp/cnc_sim_python_plugin_probe.ini";
     {
         FILE *file = std::fopen(ini, "w");
@@ -37,6 +42,12 @@ int main() {
         std::fputs("[PYTHON]\n", file);
         std::fclose(file);
     }
+    setenv("INI_FILE_NAME", ini, 1);
+    if (plugin->configure(nullptr, "PYTHON") != PLUGIN_PYTHON_NOT_INITIALIZED) {
+        std::remove(ini);
+        return 22;
+    }
+    unsetenv("INI_FILE_NAME");
     if (plugin->configure(ini, "PYTHON") != PLUGIN_PYTHON_NOT_INITIALIZED) {
         std::remove(ini);
         return 17;