diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index dd6ba832..a68e2831 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -4246,6 +4246,7 @@ class HttpCli(object):
                 self.log(t % (data_end / M, lower / M, upper / M), 6)
                 with self.u2mutex:
                     if data_end > self.u2fh.aps.get(ap_data, data_end):
+                        fhs: Optional[set[typing.BinaryIO]] = None
                         try:
                             fhs = self.u2fh.cache[ap_data].all_fhs
                             for fh in fhs:
@@ -4253,7 +4254,11 @@ class HttpCli(object):
                             self.u2fh.aps[ap_data] = data_end
                             self.log("pipe: flushed %d up2k-FDs" % (len(fhs),))
                         except Exception as ex:
-                            self.log("pipe: u2fh flush failed: %r" % (ex,))
+                            if fhs is None:
+                                err = "file is not being written to right now"
+                            else:
+                                err = repr(ex)
+                            self.log("pipe: u2fh flush failed: " + err)
 
             if lower >= data_end:
                 if data_end: