Disabling W10 mobile beta from installing? L930

[Windows Central Question]

Hi!

I have had the insider app on my phone for a while waiting on win 10 tp, but I understand that it is very buggy. Therefor i dont want to install it, and i have unchecked the "install automatically" button. The problem is that a message pops up several times a day to tell that the update will install on may 18. :O :O I have now uninstalled the insider app and the developer preview app, but it does'nt help.
How do i stop the update from installing? Its a lumia 930.

 

[xandros9]

You'll have to hard reset (erase the phone) and start over.

and not install Insider quite yet.