diff --git a/MTShell.m b/MTShell.m
index b30c22a..aebfa46 100644
--- a/MTShell.m
+++ b/MTShell.m
@@ -1139,7 +1139,7 @@ - (void) MouseTerm_osc52GetAccess
     apr_base64_encode(it, sourceCString, sourceLength);
     it += resultLength;
     /* Newer version of apr_base64_encode_len() returns the length of including the trailing \0 */
-    if (resultLength > 0 && *it - 1 == '\0')
+    if (resultLength > 0 && *(it - 1) == '\0')
         it--, allLength--;
     memcpy(it, postfix, postfix_len);