diff --git a/Lib/imaplib.py b/Lib/imaplib.py
index 2fa9012..1c0b03b 100644
--- a/Lib/imaplib.py
+++ b/Lib/imaplib.py
@@ -318,9 +318,12 @@
         self.file.close()
         try:
             self.sock.shutdown(socket.SHUT_RDWR)
-        except OSError as e:
-            # The server might already have closed the connection
-            if e.errno != errno.ENOTCONN:
+        except OSError as exc:
+            # The server might already have closed the connection.
+            # On Windows, this may result in WSAEINVAL (error 10022):
+            # An invalid operation was attempted.
+            if (exc.errno != errno.ENOTCONN
+               and getattr(exc, 'winerror', 0) != 10022):
                 raise
         finally:
             self.sock.close()
diff --git a/Lib/poplib.py b/Lib/poplib.py
index cae6950..6bcfa5c 100644
--- a/Lib/poplib.py
+++ b/Lib/poplib.py
@@ -288,9 +288,12 @@
             if sock is not None:
                 try:
                     sock.shutdown(socket.SHUT_RDWR)
-                except OSError as e:
-                    # The server might already have closed the connection
-                    if e.errno != errno.ENOTCONN:
+                except OSError as exc:
+                    # The server might already have closed the connection.
+                    # On Windows, this may result in WSAEINVAL (error 10022):
+                    # An invalid operation was attempted.
+                    if (exc.errno != errno.ENOTCONN
+                       and getattr(exc, 'winerror', 0) != 10022):
                         raise
                 finally:
                     sock.close()