Failed to load viewstate. Happening only occasionally. Tough to recreate

Question

Details of Error are given below. This error happens only occasionally / rarely / sometimes and there aren\'t any steps to reproduce it.

How can I know which Control

Answer 1

Unfortunately there is no way to see which exactly is the guilty control that is not added correctly to the control hierarchy.

There is!

Disable "Just my code" in debugging settings. And catch all thrown exceptions (check 'thrown' for Common Language Runtime in the dialog opened by Ctrl-Alt-E).

After the exception occurs, go to the nearest stack frame where the Control object is available and examine its ClientID and parents.