diff --git a/src/elogd.c b/src/elogd.c
index bfe45ac7..2a69c427 100755
--- a/src/elogd.c
+++ b/src/elogd.c
@@ -18361,7 +18361,7 @@ void show_elog_list(LOGBOOK * lbs, int past_n, int last_n, int page_n, BOOL defa
             strcpy(iattr, attr_list[i]);
             for (j = 0; j < (int) strlen(iattr); j++)
                /* replace special characters with "_", exclude any UTF-8 */
-               if (!isalnum(iattr[j]) && (iattr[j] < 128))
+               if (!isalnum(iattr[j]) && ((unsigned char)iattr[j] < 128))
                   iattr[j] = '_';
             rsprintf("\t\t<%s>", iattr);