diff --git a/passes/techmap/abc.cc b/passes/techmap/abc.cc
index a25a79ae8..e25a6facd 100644
--- a/passes/techmap/abc.cc
+++ b/passes/techmap/abc.cc
@@ -253,7 +253,7 @@ std::optional<AbcProcess> spawn_abc(const char* abc_exe, DeferredLogs &logs) {
 	char arg1[] = "-s";
 	char* argv[] = { strdup(abc_exe), arg1, nullptr };
 	if (0 != posix_spawnp(&result.pid, abc_exe, &file_actions, nullptr, argv, environ)) {
-		logs.log_error("posix_spawnp %s failed", abc_exe);
+		logs.log_error("posix_spawnp %s failed (errno=%s)", abc_exe, strerrorname_np(errno));
 		return std::nullopt;
 	}
 	free(argv[0]);