diff --git a/src/window.c b/src/window.c
index 613cc5f..95515b5 100644
--- a/src/window.c
+++ b/src/window.c
@@ -6531,7 +6531,7 @@
 	/* something failed; use the file name (truncate when too long) */
 	vim_strncpy(buf, fname, len - 1);
     }
-#if defined(MACOS_CLASSIC) || defined(OS2) || defined(MSDOS) || defined(MSWIN)
+#if defined(MACOS_CLASSIC) || defined(MSDOS) || defined(MSWIN)
     slash_adjust(buf);
 #endif
     return retval;