Asp.net Validation of viewstate MAC failed

Question

I am receiving the following error at certain times on asp.net website.

 Sys.WebForms.PageRequestManagerServerErrorException: 
 Validation of viewstate MAC f         


        

Answer 1

my problem was this piece of javascript code

$('input').each(function(ele, indx){
    this.value = this.value.toUpperCase();
});

Turns it was messing with viewstate hidden field so I changed it to below code and it worked

$('input:visible').each(function(ele, indx){
    this.value = this.value.toUpperCase();
});