diff --git a/gfx/thebes/gfxMacPlatformFontList.mm b/gfx/thebes/gfxMacPlatformFontList.mm
index b0636605c30..b7a893cb9cd 100644
--- a/gfx/thebes/gfxMacPlatformFontList.mm
+++ b/gfx/thebes/gfxMacPlatformFontList.mm
@@ -1078,6 +1078,10 @@ MacFontInfo::LoadFontFamilyData(const nsAString& aFamilyName)
         }
         CTFontRef fontRef = CTFontCreateWithFontDescriptor(faceDesc,
                                                            0.0, nullptr);
+        if (!fontRef) {
+            NS_WARNING("failed to create a CTFontRef");
+            continue;
+        }
 
         if (mLoadCmaps) {
             // face name