diff --git a/src/sphobjinv/cli/core.py b/src/sphobjinv/cli/core.py
index 731f1f1a..a7303351 100644
--- a/src/sphobjinv/cli/core.py
+++ b/src/sphobjinv/cli/core.py
@@ -190,6 +190,10 @@ def main():
         print(PrsConst.VER_TXT)
         sys.exit(0)
 
+    # At this point, need to trap for a null subparser
+    if not params[PrsConst.SUBPARSER_NAME]:
+        prs.error("No subparser selected")
+
     # Regardless of mode, insert extra blank line
     # for cosmetics
     log_print(" ", params)
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 03904999..99ba156f 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -80,7 +80,7 @@ def test_cli_no_subparser_prs_exit(self, run_cmdline_test):
         with stdio_mgr() as (in_, out_, err_):
             run_cmdline_test(["--foo"], expect=2)
 
-            assert "required: {convert,suggest}" in err_.getvalue()
+            assert "error: No subparser selected" in err_.getvalue()
 
     @pytest.mark.timeout(CLI_TEST_TIMEOUT)
     def test_cli_bad_subparser_prs_exit(self, run_cmdline_test):