Error in 2.8 - "Validation of viewstate MAC failed"

Topics: ASP.NET 2.0
Dec 13, 2013 at 10:03 PM
Edited Dec 13, 2013 at 10:05 PM
Getting the following:

Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

I added a user control where I have a simple form and a submit button, when you click the submit button it generates the error. I even replicated it by simply adding a button to the master.aspx file ... when you click that -- Boom same thing

Any ideas what this is?

by the way the error is displayed under the following link
http://localhost:53265/?id=b663b6a1-1c34-4c60-a891-c14772507b23 its some type of viewstate issue: [ViewStateException: Invalid viewstate.
Client IP: ::1
Port: 63204
Referer: http://localhost:53265/
Path: /default.aspx
User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36
ViewState: /wEPDwULLTExMTQ3OTA5NjIPZBYCZg9kFgRmD2QWAgIaDxUEMi9lZGl0b3JzL3RpbnlfbWNlXzNfNV84L3BsdWdpbnMvc3ludGF4aGlnaGxpZ2h0ZXIvMi9lZGl0b3JzL3RpbnlfbWNlXzNfNV84L3BsdWdpbnMvc3ludGF4aGlnaGxpZ2h0ZXIvMi9lZGl0b3JzL3RpbnlfbWNlXzNfNV84L3BsdWdpbnMvc3ludGF4aGlnaGxpZ2h0ZXIvMi9lZGl0b3JzL3RpbnlfbWNlXzNfNV84L3BsdWdpbnMvc3ludGF4aGlnaGxpZ2h0ZXIvZAIBD2QWBmYPDxYCHgRUZXh0BQxSZWd1bGFyIFNpdGVkZAIDD2QWBGYPFgIeCWlubmVyaHRtbAUMRXhhbXBsZSBwYWdlZAIBDxYCHwEFwgE8cD5UaGlzIGlzIGFuIGV4YW1wbGUgcGFnZS48L3A+DQo8cD4mbmJzcDtGb3IgbW9yZSBpbmZvcm1hdGlvbiBhYm91dCBwYWdlcyBhbmQgaG93IHRvIHVzZSB0aGVtLCZuYnNwO3Zpc2l0IHRoZSA8YSBocmVmPSJodHRwOi8vYmxvZ2VuZ2luZS5jb2RlcGxleC5jb20vZG9jdW1lbnRhdGlvbiI+QmxvZ0VuZ2luZS5ORVQgd2lraTwvYT4uPC9wPmQCBQ8WBB8BBQdMb2cgb2ZmHgRocmVmBRovQWNjb3VudC9sb2dpbi5hc3B4P2xvZ29mZmRkKn0fBdAozw0QO8k3T6B+EJYbjgs=]

Source File: c:\Users\jack\AppData\Local\Temp\Temporary ASP.NET Files\root\bd091d17\b1879add\App_Web_34ygjihl.2.cs Line: 0
Dec 16, 2013 at 7:23 PM
The solution to this can be found here : https://blogengine.codeplex.com/discussions/354014

It's a bug in BE 2.8