diff --git a/kitty/main.py b/kitty/main.py
index 71ddeafca..acebd2611 100644
--- a/kitty/main.py
+++ b/kitty/main.py
@@ -321,10 +321,16 @@ def macos_cmdline(argv_args: list[str]) -> list[str]:
     if ans and ans[0] == 'kitty':
         del ans[0]
     if '-1' in ans or '--single-instance' in ans:
-        # Re-exec with new argv so that the C code that handles single instance
-        # can pick up the modified argv
-        os.environ['KITTY_LAUNCHED_BY_LAUNCH_SERVICES'] = '2'  # so that use_os_log is set in the re-execed process
-        os.execl(kitty_exe(), 'kitty', *(ans + argv_args))
+        if '-1' in argv_args or '--single-instance' in argv_args:
+            # C code will already have setup single instance
+            log_error(
+                '--single-instance supplied in both command line arguments and macos-launch-services-cmdline,'
+                ' ignoring any --instance-group in macos-launch-services-cmdline')
+        else:
+            # Re-exec with new argv so that the C code that handles single instance
+            # can pick up the modified argv
+            os.environ['KITTY_LAUNCHED_BY_LAUNCH_SERVICES'] = '2'  # so that use_os_log is set in the re-execed process
+            os.execl(kitty_exe(), 'kitty', *(ans + argv_args))
     return ans + argv_args