--- a/hgext/configwizard/__init__.py
+++ b/hgext/configwizard/__init__.py
@@ -653,21 +653,19 @@ def _checkfsmonitor(ui, cw, hgversion):
         subprocess.check_output([watchman, '--version'],
                                 stderr=subprocess.STDOUT)
     except Exception:
         ui.write(WATCHMAN_NOT_FOUND)
         ui.write('\n')
         return
 
     if ui.hasconfig('extensions', 'fsmonitor'):
-        try:
-            del cw.c['extensions']['hgwatchman']
+        ext = cw.c['extensions']
+        if any([ext.pop('hgwatchman', False), ext.pop('watchman', False)]):
             ui.write('Removing extensions.hgwatchman because fsmonitor is installed\n')
-        except KeyError:
-            pass
 
         return
 
     # Mercurial 3.8+ has fsmonitor built-in.
     if hgversion >= (3, 8, 0):
         _promptnativeextension(ui, cw, 'fsmonitor', FSMONITOR_INFO)
     else:
         ui.write(FSMONITOR_NOT_AVAILABLE)