diff --git a/js/services/settings/settings.js b/js/services/settings/settings.js
index ffa8fe9..37726a5 100644
--- a/js/services/settings/settings.js
+++ b/js/services/settings/settings.js
@@ -210,8 +210,8 @@ angular.module('webui.services.settings', [])
 
   "file-allocation": {
     desc: "Specify file allocation method. none doesn't pre-allocate file space. prealloc pre-allocates file space before download begins. This may take some time depending on the size of the file. If you are using newer file systems such as ext4 (with extents support), btrfs, xfs or NTFS(MinGW build only), falloc is your best choice. It allocates large(few GiB) files almost instantly. Don't use falloc with legacy file systems such as ext3 and FAT32 because it takes almost same time as prealloc and it blocks aria2 entirely until allocation finishes. falloc may not be available if your system doesn't have posix_fallocate(3) function. Possible Values: none, prealloc, falloc Default: prealloc",
-    val: 'prealloc',
-    options: ["none", "prealloc", "falloc"]
+    val: undefined,
+    options: ["none", "prealloc", "falloc", "trunc"]
   },
 
   "follow-metalink": {