diff --git a/src/uninstall.c b/src/uninstall.c
index 78b2b7d..907ed37 100644
--- a/src/uninstall.c
+++ b/src/uninstall.c
@@ -29,7 +29,7 @@
     char	answer[10];
 
     fflush(stdout);
-    return (scanf(" %c", answer) == 1 && toupper(answer[0]) == 'Y');
+    return (scanf(" %c", answer) == 1 && toupper((unsigned char)answer[0]) == 'Y');
 }
 
     static int