- Exit MT4 if you have it running.
- Backup your metatrader4 folder.
- Copy the following files from a copy of MT4 upgraded to build 419 to your installed version, overwriting the old files (you can get a copy of the latest version at metatrader4.com):
metaeditor.exe
metalang.exe
terminal.exe
liveupdate.exe - Start MT4