How to Change your System Language completely in Windows 10 + Fixes

Hi, So in short the steps are.
1. Add language pack in the control panel, go to Language & remove others. Set default the new language as default. Also in the advance settings and don't forget to download the language pack as well.

*SideNote: If you don't see the same Icons in the control panel as in the video, you most probably have the View settings in the upper right corner setup to a different setting then I have. You should have the view on "Large Icons". Then you most definitely will see same icons as I have in the video.

2. In Region select the new language pack and push it also to the welcome screen and new users
3. In %LocalAppData% change the folder name to en-US. It Doesn't change the search problem but it does make it clickable again. Full Path is:
C:\Users\username\AppData\Local\Packages\windows.immersivecontrolpanel_cw5n1h2txyewy\LocalState.
6. Open run command, type "Lpksetup /u" ,without the quotes and uninstall the old language.
7. After language pack install update kb3124200. This should fix the issue. There are maybe some new updates which will replace this update. If you can't find the update trough windows update, try to download the standalone installer. If it is already installed, uninstall the update and reinstall it. This should invoke the fix again. Like I said, if you have one of the latest versions installed, and bearly any new updates applied, chances are that you can't reinstall the old update and you're currently stuck until Microsoft set out a new update which replace the search / index problem.

Good luck, be sure to make a backup of your files or system and or make a restore point in case something goes wrong. I am not responsible for any failure of your machine and this is at your own risk. Wish you the best of luck and let me know if this helped you out.

See ya.

*Update 4 Sept 2019:
Apparently sometimes in some newer and specific versions of Windows10 the language setting doesn't show in the control panel. I can't help you with this since I don't have a Windows10 machine were I can test this on, but I found a pretty decent reddit thread that could help you with this. Hope this helps.

reddit.com/r/Windows10/comments/8opuy7/language…