diff --git a/src/os_win32.c b/src/os_win32.c
index 91bd18a..73af6a1 100644
--- a/src/os_win32.c
+++ b/src/os_win32.c
@@ -7768,11 +7768,14 @@
 	// Also, unset wildignore to not be influenced by this option.
 	// The arguments specified in command-line should be kept even if
 	// encoding options were changed.
-	do_cmdline_cmd((char_u *)":let SaVe_ISF = &isf|set isf+=(,)");
-	do_cmdline_cmd((char_u *)":let SaVe_WIG = &wig|set wig=");
+	// Use :legacy so that it also works when in Vim9 script.
+	do_cmdline_cmd((char_u *)":legacy let g:SaVe_ISF = &isf|set isf+=(,)");
+	do_cmdline_cmd((char_u *)":legacy let g:SaVe_WIG = &wig|set wig=");
 	alist_expand(fnum_list, used_alist_count);
-	do_cmdline_cmd((char_u *)":let &isf = SaVe_ISF|unlet SaVe_ISF");
-	do_cmdline_cmd((char_u *)":let &wig = SaVe_WIG|unlet SaVe_WIG");
+	do_cmdline_cmd(
+		(char_u *)":legacy let &isf = g:SaVe_ISF|unlet g:SaVe_ISF");
+	do_cmdline_cmd(
+		(char_u *)":legacy let &wig = g:SaVe_WIG|unlet g:SaVe_WIG");
     }
 
     // If wildcard expansion failed, we are editing the first file of the