--- a/toolkit/modules/Troubleshoot.jsm
+++ b/toolkit/modules/Troubleshoot.jsm
@@ -232,18 +232,19 @@ var dataProviders = {
     } catch (e) {
       data.autoStartStatus = -1;
     }
 
     data.styloBuild = AppConstants.MOZ_STYLO;
     data.styloDefault = Services.prefs.getDefaultBranch(null)
                                 .getBoolPref("layout.css.servo.enabled", false);
     data.styloResult =
-      !!env.get("STYLO_FORCE_ENABLED") ||
-      Services.prefs.getBoolPref("layout.css.servo.enabled", false);
+      AppConstants.MOZ_STYLO &&
+      (!!env.get("STYLO_FORCE_ENABLED") ||
+       Services.prefs.getBoolPref("layout.css.servo.enabled", false));
 
     const keyGoogle = Services.urlFormatter.formatURL("%GOOGLE_API_KEY%").trim();
     data.keyGoogleFound = keyGoogle != "no-google-api-key" && keyGoogle.length > 0;
 
     const keyMozilla = Services.urlFormatter.formatURL("%MOZILLA_API_KEY%").trim();
     data.keyMozillaFound = keyMozilla != "no-mozilla-api-key" && keyMozilla.length > 0;
 
     done(data);