diff --git a/assembler/assembler.c b/assembler/assembler.c
index 121ce32..6647ab7 100644
--- a/assembler/assembler.c
+++ b/assembler/assembler.c
@@ -172,6 +172,9 @@ int try_expand_macro(struct assembler_state *state, char **line) {
 	if (strstr(*line, "macro") == *line + 1) { // Cannot expand macros while defining them
 		return 0;
 	}
+	if (strstr(*line, "undefine") == *line + 1) { // Should not expand while removing
+		return 0;
+	}
 	if (strstr(*line, "ifdef") == *line + 1) { // Should not expand when testing for existence
 		return 0;
 	}
diff --git a/assembler/directives.c b/assembler/directives.c
index f68f14a..eeb7875 100644
--- a/assembler/directives.c
+++ b/assembler/directives.c
@@ -433,6 +433,8 @@ int handle_undef(struct assembler_state *state, char **argv, int argc) {
 		return 1;
 	}
 
+	scas_log(L_DEBUG, "Looking for %s", argv[0]);
+
 	int i;
 	for (i = 0; i < state->macros->length; i++) {
 		macro_t *m = state->macros->items[i];