ASP.NET CheckBox does not fire CheckedChanged event when unchecking

Question

I have a CheckBox on an ASP.NET Content Form like so:

Answer 1

I had the same problem. I have spent a lot of time on it and finally have solved it.

In my case the Checkbox was disabled by default:

It turns ViewState isn't loaded for disabled or invisible controls. So remove Enabled="false" or Visible="false" and it will work as expeceted. And of course ViewState shouldn't be disabled.