diff --git a/src/calibre/utils/copy_files.py b/src/calibre/utils/copy_files.py
index 7cddf9b9b0..540b96bf31 100644
--- a/src/calibre/utils/copy_files.py
+++ b/src/calibre/utils/copy_files.py
@@ -91,7 +91,7 @@ class WindowsFileCopier:
         for path, file_id in self.path_to_fileid_map.items():
             self.fileid_to_paths_map[file_id].add(path)
         for src in self.copy_map:
-            self.path_to_handle_map = self._open_file(src)
+            self.path_to_handle_map[src] = self._open_file(src)
 
     def __exit__(self, *a) -> None:
         for h in self.path_to_handle_map.values():
diff --git a/src/calibre/utils/copy_files_test.py b/src/calibre/utils/copy_files_test.py
index 2b0c979612..1d7394bb39 100644
--- a/src/calibre/utils/copy_files_test.py
+++ b/src/calibre/utils/copy_files_test.py
@@ -7,6 +7,7 @@ import tempfile
 import time
 import unittest
 
+from calibre import walk
 from calibre.constants import iswindows
 
 from .copy_files import copy_tree
@@ -79,6 +80,14 @@ class TestCopyFiles(unittest.TestCase):
         if not iswindows:
             self.ae(os.readlink(self.d('link.extra')), 'sub/a')
 
+        self.reset()
+        src, dest = self.s(), self.d()
+        if iswindows:
+            with open(self.s('sub/a')) as locked:
+                locked
+                self.assertRaises(IOError, copy_tree, src, dest)
+                self.ae(os.listdir(self.d()), ['sub'])
+                self.assertFalse(tuple(walk(self.d())))
 
 def find_tests():
     return unittest.defaultTestLoader.loadTestsFromTestCase(TestCopyFiles)