I tried to chat online with HP customer support to talk about my all-in-one, but when it tried to connect to the technician, I recieved this error.
validation of viewstate MAC failed .. If this app is hosted by a web farm or cluster ensure that <machinekey> config specifies the same validationkey and validation algorithm
The source code that generated this unhandled exception can only be shown when compiled in debug mode. To enable this, please follow one of the below steps, then request the URL:
1. Add a "Debug=true" directive at the top of the file that generated the error. Example:
<%@ Page Language="C#" Debug="true" %>