diff --git a/js/ui/sessionMode.js b/js/ui/sessionMode.js
index ab9c61b8c..a98782871 100644
--- a/js/ui/sessionMode.js
+++ b/js/ui/sessionMode.js
@@ -75,11 +75,6 @@ const _modes = {
             }
 };
 
-function modeExists(mode) {
-    let modes = Object.getOwnPropertyNames(_modes);
-    return modes.indexOf(mode) != -1;
-}
-
 function listModes() {
     let modes = Object.getOwnPropertyNames(_modes);
     for (let i = 0; i < modes.length; i++)
diff --git a/src/main.c b/src/main.c
index 1f200392d..98528906b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -393,12 +393,6 @@ main (int argc, char **argv)
 
   _shell_global_init ("session-mode", session_mode, NULL);
 
-  if (!_shell_global_has_valid_session_mode (shell_global_get ()))
-    {
-      g_printerr ("\"%s\" is not a valid mode.\n", session_mode);
-      exit(1);
-    }
-
   ecode = meta_run ();
 
   if (g_getenv ("GNOME_SHELL_ENABLE_CLEANUP"))
diff --git a/src/shell-global-private.h b/src/shell-global-private.h
index 194312d65..786719f5b 100644
--- a/src/shell-global-private.h
+++ b/src/shell-global-private.h
@@ -13,7 +13,6 @@ void _shell_global_set_plugin      (ShellGlobal  *global,
 
 GjsContext *_shell_global_get_gjs_context (ShellGlobal  *global);
 
-gboolean _shell_global_has_valid_session_mode (ShellGlobal *global);
 gboolean _shell_global_check_xdnd_event (ShellGlobal  *global,
                                          XEvent       *xev);
 
diff --git a/src/shell-global.c b/src/shell-global.c
index ab3b59ea4..10fb0b35e 100644
--- a/src/shell-global.c
+++ b/src/shell-global.c
@@ -585,21 +585,6 @@ shell_global_set_stage_input_mode (ShellGlobal         *global,
     }
 }
 
-gboolean
-_shell_global_has_valid_session_mode (ShellGlobal *global)
-{
-  char *script;
-  int status;
-
-  script = g_strdup_printf ("imports.ui.environment.init();"
-                            "imports.ui.sessionMode.modeExists('%s') || 1;",
-                            global->session_mode);
-  gjs_context_eval (global->js_context, script, -1, "<sessionMode.js>", &status, NULL);
-  g_free (script);
-
-  return status == 0;
-}
-
 /**
  * shell_global_set_cursor:
  * @global: A #ShellGlobal