Validation of viewstate MAC failed when on page for 20+ minutes
问题 If you open a web page on one of the websites hosted on our server, leave it for 20 minutes and then submit a form, a Validation of viewstate MAC failed. error occurs. What possible reasons could there be for this? 回答1: There's a few reasons this can happen: Auto-Generated Machine Keys: If your application pools have the default idle timeout of 20 minutes AND you're using auto-generated validation and decryption keys then each time the pool starts it will generate a new set of keys. This