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

I had this same issue and it was due to a Gridview (generated from a vb code) on the page which had sorting enabled. Disabling Sort fixed my issue. I do not have this problem with the gridviews created using a SQLdatasource.