diff --git a/copyparty/ftpd.py b/copyparty/ftpd.py
index 5482436b..aa46bf97 100644
--- a/copyparty/ftpd.py
+++ b/copyparty/ftpd.py
@@ -249,7 +249,8 @@ class FtpFs(AbstractedFS):
                 need_unlink = False
                 td = 0
 
-        if w and need_unlink:
+        # Don't unlink file for append mode
+        if w and need_unlink and "a" not in mode:
             if td >= -1 and td <= self.args.ftp_wt:
                 # within permitted timeframe; unlink and accept
                 do_it = True