Invalid viewstate

Question

Invalid viewstate

-- -- 957

Hi

I am getting below on my webform;

Exception Type: System.Web.HttpException
Exception: 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.

At present it seems the problem only seems to effect iPhone. This webform is being redirected to from our main non asp.net site from Wix. The suspicion is that safari on iPhone is getting confused regarding view state during redirect.

Has anyone come across this and has a solution?

Thanks

Regards

AgaveJoe 30,126 Reputation points

2021-09-02T11:16:54.953+00:00

Has anyone come across this and has a solution?

Yes. This is a well documented error in web forms. ViewState is an input field encrypted by the local machine key. Typically what happens is the machine key changes between post backs which invalids the ViewState. The solution is to set a specific machine key as recommended in the error message.

Google Search: Validation of viewstate MAC failed
-- -- 957 Reputation points

2021-09-02T14:59:25.237+00:00
Hi

We have the following in web.config but that has not helped.

<system.web> <machineKey validationKey="<snipped>" decryptionKey="<snipped>" validation="SHA1" decryption="AES" /> </system.web>

Regards
AgaveJoe 30,126 Reputation points

2021-09-02T16:09:46.047+00:00

The suspicion is that safari on iPhone is getting confused regarding view state during redirect.

ViewState is a hidden input field within the web form that maintains the state of user entries between post back. A redirect does not pass HTML form fields which includes the ViewState hidden field. Secondly, the first time a web form loads, ViewState is empty because the user has not entered any values. Keep in mind, this happens on the server. My best guess is the page in question is cached by the Safari browser. The cached page has a ViewState that was encrypted by a machine key that no longer exists. Try clearing the browser cache.

You might try Safari support too.

Your answer

AgaveJoe 30,126 Reputation points

2021-09-02T11:16:54.953+00:00

Has anyone come across this and has a solution?

Yes. This is a well documented error in web forms. ViewState is an input field encrypted by the local machine key. Typically what happens is the machine key changes between post backs which invalids the ViewState. The solution is to set a specific machine key as recommended in the error message.

Google Search: Validation of viewstate MAC failed
-- -- 957 Reputation points

2021-09-02T14:59:25.237+00:00

Hi

We have the following in web.config but that has not helped.

<system.web> <machineKey validationKey="<snipped>" decryptionKey="<snipped>" validation="SHA1" decryption="AES" /> </system.web>

Regards
AgaveJoe 30,126 Reputation points

2021-09-02T16:09:46.047+00:00

The suspicion is that safari on iPhone is getting confused regarding view state during redirect.

ViewState is a hidden input field within the web form that maintains the state of user entries between post back. A redirect does not pass HTML form fields which includes the ViewState hidden field. Secondly, the first time a web form loads, ViewState is empty because the user has not entered any values. Keep in mind, this happens on the server. My best guess is the page in question is cached by the Safari browser. The cached page has a ViewState that was encrypted by a machine key that no longer exists. Try clearing the browser cache.

You might try Safari support too.

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Invalid viewstate

Your answer