diff --git a/steam_helper/steam.c b/steam_helper/steam.c
index 7e70a989..fc13d697 100644
--- a/steam_helper/steam.c
+++ b/steam_helper/steam.c
@@ -680,7 +680,7 @@ static void setup_steam_files(void)
     }
 
     pos += strappend( &buf, &buf_size, pos, "}\n" );
-    write_file( L"C:\\Program Files (x86)\\Steam\\steamapps\\libraryfolders.vdf", buf, buf_size );
+    write_file( L"C:\\Program Files (x86)\\Steam\\steamapps\\libraryfolders.vdf", buf, pos );
 }
 
 #ifndef DIRECTORY_QUERY