diff --git a/unix/uxpgnt.c b/unix/uxpgnt.c
index c9036eed..0329f6b9 100644
--- a/unix/uxpgnt.c
+++ b/unix/uxpgnt.c
@@ -331,6 +331,7 @@ static int unix_add_keyfile(const char *filename_str)
     while (1) {
         char *passphrase = askpass(err);
         sfree(err);
+        err = NULL;
         if (!passphrase)
             break;