It doesn't happen every time, but it does seem to happen around 10 times a day on some sites. I'll check your your link and reply back when I get a chance to dig deeper

Hi, I've applied latest hot fix and it seem to be resolved, I've changed default host name for my site but I revert every change i've done to verify that the error is gone... Thanks Francis Harvey

Hi Francis, Thanks for the update. Which version exactly have you used before applying the hotfix? Please let us know if you encounter any further errors. Regards, Zdenek C.

Hi Zdenek, I did not apply any hotfix before, so it is the installer version that possibly contains the bug, The hot fixe applied was the latest one, i think it is 5.5R2.37, I'll verify... Thanks Francis Harvey

Hi Juraj, It appear the problem is not gone, It happen sometimes, but not locally on my computer, It happen only on remote machine, Is the machine key config should be set even if i don't use any cluster or web farms ?? Thank you Francis Harvey

Hello, Please apply the latest hot fix as there were some issues with the 32th hot fix. These issues are mentioned in the comments section under this blog post. Best regards, Boris Pocatko

Hello, I tried to allow the cookies on the linked page and it seems to be working fine. Could you please let me know what problems do still persist? Best regards, Boris Pocatko

Hello. I did not see whole error message or stacktrace, but I far as I know, this issue ordinary happens if somebody do a postback before the whole viewstate of page is loaded, e.g. if viewstate is too long and/or the connection is slow and user submit some button before th...

Hi, In older version there was a bug in full page caching which was causing this error. But, in most cases this error is caused by the things described in the error message (machine key configuration and web farms) or if the application is restarted/killed for some reason a...

Hello, This issue usually comes up when postback occurs before the whole viewstate of the page is loaded. It's most likely an issue with custom code somewhere on the page as this is an ASP.NET error, not specific to Kentico. If you are unable to find the cause please give u...