diff --git a/src/os_mswin.c b/src/os_mswin.c
index 5e96da8..a5e10be 100644
--- a/src/os_mswin.c
+++ b/src/os_mswin.c
@@ -2564,9 +2564,11 @@
 	switch (data->dwData)
 	{
 	case COPYDATA_ENCODING:
+# ifdef FEAT_MBYTE
 	    /* Remember the encoding that the client uses. */
 	    vim_free(client_enc);
 	    client_enc = enc_canonize((char_u *)data->lpData);
+# endif
 	    return 1;
 
 	case COPYDATA_KEYS: