diff --git a/include/MacStd/CoreFoundation.hpp b/include/MacStd/CoreFoundation.hpp
index cc88887..d71c0fa 100644
--- a/include/MacStd/CoreFoundation.hpp
+++ b/include/MacStd/CoreFoundation.hpp
@@ -87,14 +87,14 @@ namespace macstd {
 		static std::string message(CFErrorRef error)
 		{
 			macstd::cfstring description(CFErrorCopyDescription(error));
-			if (description && CFStringGetLength(description) > 0) {
+			if (description.valid() && CFStringGetLength(description) > 0) {
 				auto str = CFStringGetCStringPtr(description, kCFStringEncodingUTF8);
 				if (str)
 					return str;
 			}
 			std::string msg("Core Foundation error " + std::to_string(CFErrorGetCode(error)));
 			macstd::cfstring domain(CFErrorGetDomain(error));
-			if (domain && CFStringGetLength(domain) > 0) {
+			if (domain.valid() && CFStringGetLength(domain) > 0) {
 				auto str = CFStringGetCStringPtr(domain, kCFStringEncodingUTF8);
 				if (str)
 					msg += std::string(", domain ") + str;