Invalid_Viewstate means that the viewstate the client sends to the server
doesn't conform to what the server expects. The viewstate contains the
content of controls on your webpage, that is, the text in your textbox,
the state of your checkbox, and so on.
Invalid_Viewstate can have several causes:
- You changed the application while the client was connected
- The client browser has changed the viewstate variable (the viewstate is
a hidden field on your webpage. The browser shouldn't change it.)
- You're using a clustered web server and the second request from the
client is handled by a different server
- The client hot-swapped his ethernet adapter while browsing your website
- And probably some more causes I don't know about
Generally, if none of your users are complaining, I wouldn't worry about
it.
Regards,
Wessel